456ec1c2f4
We are not handling 'S' scalar dependencies correctly and have at least the following miscompiles related to that: [LoopInterchange] incorrect handling of scalar dependencies and dependence vectors starting with ">" #54176 [LoopInterchange] Interchange breaks program correctness #46867 [LoopInterchange] Loops should not interchanged due to dependencies #47259 [LoopInterchange] Loops should not interchanged due to control flow #47401 This patch does no longer insert the "S" dependency/direction into the dependency matrix, so a dependency is never "S". We seem to have forgotten what the exact meaning is of this dependency type, and don't see why it should be treated differently. We prefer correctness over incorrect and more aggressive results. I.e., this prevents the miscompiles at the expense of handling less cases, i.e. making interchange more pessimistic. However, some of the cases that are now rejected for dependence analysis reasons, were rejected before too but for other reasons (e.g. profitability). So at least for the llvm regression tests, the number of regression are very reasonable. This should be a stopgap. We would like to get interchange enabled by default and thus prefer correctness over unsafe transforms, and later see if we can get solve the regressions.
342 lines
14 KiB
LLVM
342 lines
14 KiB
LLVM
; Remove 'S' Scalar Dependencies #119345
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; Scalar dependencies are not handled correctly, so they were removed to avoid
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; miscompiles. The loop nest in this test case used to be interchanged, but it's
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; no longer triggering. XFAIL'ing this test to indicate that this test should
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; interchanged if scalar deps are handled correctly.
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;
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; XFAIL: *
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; RUN: opt < %s -passes=loop-interchange -cache-line-size=64 -pass-remarks-missed='loop-interchange' -verify-loop-lcssa -pass-remarks-output=%t -S
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; RUN: FileCheck --input-file %t --check-prefix REMARK %s
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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@A = common global [100 x [100 x i32]] zeroinitializer
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@C = common global [100 x [100 x i32]] zeroinitializer
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@X = common global i32 0
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@Y = common global i64 0
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@F = common global float 0.0
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; We cannot interchange this loop at the moment, because iv.outer.next is
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; produced in the outer loop latch and used in the loop exit block. If the inner
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; loop body is not executed, the outer loop latch won't be executed either
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; after interchanging.
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; REMARK: UnsupportedExitPHI
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; REMARK-NEXT: lcssa_01
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define void @lcssa_01() {
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entry:
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%cmp21 = icmp sgt i64 100, 1
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br i1 %cmp21, label %outer.ph, label %for.end16
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outer.ph: ; preds = %entry
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%cmp218 = icmp sgt i64 100, 1
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br label %outer.header
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outer.header: ; preds = %outer.inc, %outer.ph
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%iv.outer = phi i64 [ 1, %outer.ph ], [ %iv.outer.next, %outer.inc ]
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br i1 %cmp218, label %for.body3, label %outer.inc
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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store i32 %add, ptr %arrayidx5
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %for.body3, %outer.header
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%iv.outer.next.lcssa = phi i64 [ %iv.outer.next, %outer.inc ]
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store i64 %iv.outer.next.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit, %entry
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ret void
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}
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; REMARK: UnsupportedExitPHI
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; REMARK-NEXT: lcssa_02
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define void @lcssa_02() {
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entry:
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%cmp21 = icmp sgt i64 100, 1
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br i1 %cmp21, label %outer.ph, label %for.end16
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outer.ph: ; preds = %entry
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%cmp218 = icmp sgt i64 100, 1
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br label %outer.header
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outer.header: ; preds = %outer.inc, %outer.ph
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%iv.outer = phi i64 [ 1, %outer.ph ], [ %iv.outer.next, %outer.inc ]
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br i1 %cmp218, label %for.body3, label %outer.inc
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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store i32 %add, ptr %arrayidx5
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %for.body3, %outer.header
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%iv.inner.end = phi i64 [ 0, %outer.header ], [ %iv.inner.next, %for.body3 ]
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%iv.inner.end.lcssa = phi i64 [ %iv.inner.end, %outer.inc ]
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store i64 %iv.inner.end.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit, %entry
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ret void
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}
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; REMARK: Interchanged
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; REMARK-NEXT: lcssa_03
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define void @lcssa_03() {
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entry:
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br label %outer.header
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outer.header: ; preds = %outer.inc, %entry
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%iv.outer = phi i64 [ 1, %entry ], [ %iv.outer.next, %outer.inc ]
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br label %for.body3
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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store i32 %add, ptr %arrayidx5
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %for.body3
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%iv.inner.lcssa = phi i64 [ %iv.inner, %for.body3 ]
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%iv.inner.lcssa.lcssa = phi i64 [ %iv.inner.lcssa, %outer.inc ]
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store i64 %iv.inner.lcssa.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit
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ret void
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}
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; Loops with floating point reductions are interchanged with fastmath.
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; REMARK: Interchanged
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; REMARK-NEXT: lcssa_04
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define void @lcssa_04() {
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entry:
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br label %outer.header
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outer.header: ; preds = %outer.inc, %entry
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%iv.outer = phi i64 [ 1, %entry ], [ %iv.outer.next, %outer.inc ]
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%float.outer = phi float [ 1.000000e+00, %entry ], [ %float.outer.next, %outer.inc ]
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br label %for.body3
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%float.inner = phi float [ %float.inner.next, %for.body3 ], [ %float.outer, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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%float.inner.next = fadd fast float %float.inner, 1.000000e+00
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store i32 %add, ptr %arrayidx5
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %for.body3
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%float.outer.next = phi float [ %float.inner.next, %for.body3 ]
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%float.outer.lcssa = phi float [ %float.outer.next, %outer.inc ]
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store float %float.outer.lcssa, ptr @F
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br label %for.end16
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for.end16: ; preds = %for.exit
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ret void
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}
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; PHI node in inner latch with multiple predecessors.
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; REMARK: Interchanged
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; REMARK-NEXT: lcssa_05
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define void @lcssa_05(ptr %ptr, i1 %arg) {
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entry:
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br label %outer.header
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outer.header: ; preds = %outer.inc, %entry
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%iv.outer = phi i64 [ 1, %entry ], [ %iv.outer.next, %outer.inc ]
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br label %for.body3
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for.body3: ; preds = %bb3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %bb3 ], [ 1, %outer.header ]
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br i1 %arg, label %bb2, label %bb3
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bb2: ; preds = %for.body3
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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br label %bb3
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bb3: ; preds = %bb2, %for.body3
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%addp = phi i32 [ %add, %bb2 ], [ 0, %for.body3 ]
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store i32 %addp, ptr %ptr
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %bb3
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%iv.inner.lcssa = phi i64 [ %iv.inner, %bb3 ]
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%iv.inner.lcssa.lcssa = phi i64 [ %iv.inner.lcssa, %outer.inc ]
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store i64 %iv.inner.lcssa.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit
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ret void
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}
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; REMARK: UnsupportedExitPHI
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; REMARK-NEXT: lcssa_06
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define void @lcssa_06(ptr %ptr, ptr %ptr1, i1 %arg) {
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entry:
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br label %outer.header
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outer.header: ; preds = %outer.inc, %entry
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%iv.outer = phi i64 [ 1, %entry ], [ %iv.outer.next, %outer.inc ]
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br i1 %arg, label %for.body3, label %outer.inc
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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store i32 %add, ptr %ptr1
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.inc, label %for.body3
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outer.inc: ; preds = %for.body3, %outer.header
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%sv = phi i64 [ 0, %outer.header ], [ 1, %for.body3 ]
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%sv.lcssa = phi i64 [ %sv, %outer.inc ]
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store i64 %sv.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit
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ret void
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}
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; REMARK: Interchanged
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; REMARK-NEXT: lcssa_07
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define void @lcssa_07() {
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entry:
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br label %outer.header
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outer.header: ; preds = %outer.inc, %entry
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%iv.outer = phi i64 [ 1, %entry ], [ %iv.outer.next, %outer.inc ]
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br label %for.body3
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for.body3: ; preds = %for.body3, %outer.header
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%iv.inner = phi i64 [ %iv.inner.next, %for.body3 ], [ 1, %outer.header ]
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%arrayidx5 = getelementptr inbounds [100 x [100 x i32]], ptr @A, i64 0, i64 %iv.inner, i64 %iv.outer
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%vA = load i32, ptr %arrayidx5
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%arrayidx9 = getelementptr inbounds [100 x [100 x i32]], ptr @C, i64 0, i64 %iv.inner, i64 %iv.outer
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%vC = load i32, ptr %arrayidx9
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%add = add nsw i32 %vA, %vC
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store i32 %add, ptr %arrayidx5
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%iv.inner.next = add nuw nsw i64 %iv.inner, 1
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%exitcond = icmp eq i64 %iv.inner.next, 100
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br i1 %exitcond, label %outer.bb, label %for.body3
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outer.bb: ; preds = %for.body3
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%iv.inner.lcssa = phi i64 [ %iv.inner, %for.body3 ]
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br label %outer.inc
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outer.inc: ; preds = %outer.bb
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%iv.outer.next = add nsw i64 %iv.outer, 1
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%cmp = icmp eq i64 %iv.outer.next, 100
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br i1 %cmp, label %outer.header, label %for.exit
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for.exit: ; preds = %outer.inc
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%iv.inner.lcssa.lcssa = phi i64 [ %iv.inner.lcssa, %outer.inc ]
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store i64 %iv.inner.lcssa.lcssa, ptr @Y
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br label %for.end16
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for.end16: ; preds = %for.exit
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ret void
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}
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; Should not crash when the outer header branches to
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; both the inner loop and the outer latch, and there
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; is an lcssa phi node outside the loopnest.
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; REMARK: Interchanged
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; REMARK-NEXT: lcssa_08
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define i64 @lcssa_08(ptr %Arr, i1 %arg) {
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entry:
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br label %for1.header
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for1.header: ; preds = %for1.inc, %entry
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%indvars.iv23 = phi i64 [ 0, %entry ], [ %indvars.iv.next24, %for1.inc ]
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br i1 %arg, label %for2, label %for1.inc
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for2: ; preds = %for2, %for1.header
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%indvars.iv = phi i64 [ 0, %for1.header ], [ %indvars.iv.next.3, %for2 ]
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%arrayidx = getelementptr inbounds [100 x [100 x i64]], ptr %Arr, i64 0, i64 %indvars.iv, i64 %indvars.iv23
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%lv = load i64, ptr %arrayidx, align 4
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%indvars.iv.next.3 = add nuw nsw i64 %indvars.iv, 1
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%exit1 = icmp eq i64 %indvars.iv.next.3, 100
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br i1 %exit1, label %for1.inc, label %for2
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for1.inc: ; preds = %for2, %for1.header
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%indvars.iv.next24 = add nuw nsw i64 %indvars.iv23, 1
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%exit2 = icmp eq i64 %indvars.iv.next24, 100
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br i1 %exit2, label %for1.loopexit, label %for1.header
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for1.loopexit: ; preds = %for1.inc
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%sum.outer.lcssa = phi i64 [ %indvars.iv23, %for1.inc ]
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ret i64 %sum.outer.lcssa
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}
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