b9808e5660
Loop unrolling tends to produce chains of `%x1 = add %x0, 1; %x2 = add %x1, 1; ...` with one add per unrolled iteration. This patch simplifies these adds to `%xN = add %x0, N` directly during unrolling, rather than waiting for InstCombine to do so. The motivation for this is that having a single add (rather than an add chain) on the induction variable makes it a simple recurrence, which we specially recognize in a number of places. This allows InstCombine to directly perform folds with that knowledge, instead of first folding the add chains, and then doing other folds in another InstCombine iteration. Due to the reduced number of InstCombine iterations, this also results in a small compile-time improvement. Differential Revision: https://reviews.llvm.org/D153540
300 lines
10 KiB
LLVM
300 lines
10 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -S -passes=loop-unroll < %s | FileCheck %s
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; RUN: opt -S -passes='require<opt-remark-emit>,loop(loop-unroll-full)' < %s | FileCheck %s
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; Unroll twice, with first loop exit kept
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define void @s32_max1(i32 %n, ptr %p) {
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;
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; CHECK-LABEL: @s32_max1(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 1
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[N]]
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; CHECK-NEXT: store i32 [[N]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC:%.*]] = add i32 [[N]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[N]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY_1:%.*]], label [[DO_END:%.*]]
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; CHECK: do.body.1:
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; CHECK-NEXT: [[ARRAYIDX_1:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC]]
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; CHECK-NEXT: store i32 [[INC]], ptr [[ARRAYIDX_1]], align 4
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; CHECK-NEXT: br label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 1
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp slt i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 1 times
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do.end:
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ret void
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}
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; Unroll thrice, with first loop exit kept
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define void @s32_max2(i32 %n, ptr %p) {
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;
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; CHECK-LABEL: @s32_max2(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 2
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[N]]
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; CHECK-NEXT: store i32 [[N]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC:%.*]] = add i32 [[N]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[N]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY_1:%.*]], label [[DO_END:%.*]]
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; CHECK: do.body.1:
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; CHECK-NEXT: [[ARRAYIDX_1:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC]]
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; CHECK-NEXT: store i32 [[INC]], ptr [[ARRAYIDX_1]], align 4
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; CHECK-NEXT: [[INC_1:%.*]] = add i32 [[N]], 2
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; CHECK-NEXT: [[ARRAYIDX_2:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC_1]]
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; CHECK-NEXT: store i32 [[INC_1]], ptr [[ARRAYIDX_2]], align 4
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; CHECK-NEXT: br label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 2
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp slt i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 2 times
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do.end:
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ret void
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}
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; Should not be unrolled
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define void @s32_maxx(i32 %n, i32 %x, ptr %p) {
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;
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; CHECK-LABEL: @s32_maxx(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[X:%.*]], [[N:%.*]]
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[I_0:%.*]] = phi i32 [ [[N]], [[ENTRY:%.*]] ], [ [[INC:%.*]], [[DO_BODY]] ]
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[I_0]]
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; CHECK-NEXT: store i32 [[I_0]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC]] = add i32 [[I_0]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I_0]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY]], label [[DO_END:%.*]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %x, %n
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp slt i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or x times
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do.end:
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ret void
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}
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; Should not be unrolled
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define void @s32_max2_unpredictable_exit(i32 %n, i32 %x, ptr %p) {
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;
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; CHECK-LABEL: @s32_max2_unpredictable_exit(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 2
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[I_0:%.*]] = phi i32 [ [[N]], [[ENTRY:%.*]] ], [ [[INC:%.*]], [[IF_END:%.*]] ]
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; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[I_0]], [[X:%.*]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_END:%.*]], label [[IF_END]]
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; CHECK: if.end:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[I_0]]
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; CHECK-NEXT: store i32 [[I_0]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC]] = add i32 [[I_0]], 1
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; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[I_0]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP1]], label [[DO_BODY]], label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 2
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %if.end ]
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%cmp = icmp eq i32 %i.0, %x
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br i1 %cmp, label %do.end, label %if.end ; unpredictable
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if.end:
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp1 = icmp slt i32 %i.0, %add
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br i1 %cmp1, label %do.body, label %do.end ; taken either 0 or 2 times
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do.end:
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ret void
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}
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; Unroll twice, with first loop exit kept
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define void @u32_max1(i32 %n, ptr %p) {
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;
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; CHECK-LABEL: @u32_max1(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 1
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[N]]
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; CHECK-NEXT: store i32 [[N]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC:%.*]] = add i32 [[N]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[N]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY_1:%.*]], label [[DO_END:%.*]]
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; CHECK: do.body.1:
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; CHECK-NEXT: [[ARRAYIDX_1:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC]]
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; CHECK-NEXT: store i32 [[INC]], ptr [[ARRAYIDX_1]], align 4
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; CHECK-NEXT: br label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 1
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp ult i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 1 times
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do.end:
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ret void
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}
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; Unroll thrice, with first loop exit kept
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define void @u32_max2(i32 %n, ptr %p) {
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;
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; CHECK-LABEL: @u32_max2(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 2
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[N]]
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; CHECK-NEXT: store i32 [[N]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC:%.*]] = add i32 [[N]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[N]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY_1:%.*]], label [[DO_END:%.*]]
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; CHECK: do.body.1:
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; CHECK-NEXT: [[ARRAYIDX_1:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC]]
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; CHECK-NEXT: store i32 [[INC]], ptr [[ARRAYIDX_1]], align 4
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; CHECK-NEXT: [[INC_1:%.*]] = add i32 [[N]], 2
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; CHECK-NEXT: [[ARRAYIDX_2:%.*]] = getelementptr i32, ptr [[P]], i32 [[INC_1]]
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; CHECK-NEXT: store i32 [[INC_1]], ptr [[ARRAYIDX_2]], align 4
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; CHECK-NEXT: br label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 2
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp ult i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or 2 times
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do.end:
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ret void
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}
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; Should not be unrolled
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define void @u32_maxx(i32 %n, i32 %x, ptr %p) {
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;
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; CHECK-LABEL: @u32_maxx(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[X:%.*]], [[N:%.*]]
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[I_0:%.*]] = phi i32 [ [[N]], [[ENTRY:%.*]] ], [ [[INC:%.*]], [[DO_BODY]] ]
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[I_0]]
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; CHECK-NEXT: store i32 [[I_0]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC]] = add i32 [[I_0]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[I_0]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_BODY]], label [[DO_END:%.*]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %x, %n
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %do.body ]
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp = icmp ult i32 %i.0, %add
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br i1 %cmp, label %do.body, label %do.end ; taken either 0 or x times
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do.end:
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ret void
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}
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; Should not be unrolled
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define void @u32_max2_unpredictable_exit(i32 %n, i32 %x, ptr %p) {
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;
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; CHECK-LABEL: @u32_max2_unpredictable_exit(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[ADD:%.*]] = add i32 [[N:%.*]], 2
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; CHECK-NEXT: br label [[DO_BODY:%.*]]
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; CHECK: do.body:
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; CHECK-NEXT: [[I_0:%.*]] = phi i32 [ [[N]], [[ENTRY:%.*]] ], [ [[INC:%.*]], [[IF_END:%.*]] ]
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; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[I_0]], [[X:%.*]]
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; CHECK-NEXT: br i1 [[CMP]], label [[DO_END:%.*]], label [[IF_END]]
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; CHECK: if.end:
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr i32, ptr [[P:%.*]], i32 [[I_0]]
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; CHECK-NEXT: store i32 [[I_0]], ptr [[ARRAYIDX]], align 4
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; CHECK-NEXT: [[INC]] = add i32 [[I_0]], 1
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ult i32 [[I_0]], [[ADD]]
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; CHECK-NEXT: br i1 [[CMP1]], label [[DO_BODY]], label [[DO_END]]
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; CHECK: do.end:
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; CHECK-NEXT: ret void
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;
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entry:
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%add = add i32 %n, 2
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br label %do.body
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do.body:
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%i.0 = phi i32 [ %n, %entry ], [ %inc, %if.end ]
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%cmp = icmp eq i32 %i.0, %x
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br i1 %cmp, label %do.end, label %if.end ; unpredictable
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if.end:
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%arrayidx = getelementptr i32, ptr %p, i32 %i.0
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store i32 %i.0, ptr %arrayidx, align 4
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%inc = add i32 %i.0, 1
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%cmp1 = icmp ult i32 %i.0, %add
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br i1 %cmp1, label %do.body, label %do.end ; taken either 0 or 2 times
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do.end:
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ret void
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}
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