50b9ca4dda
After https://github.com/llvm/llvm-project/pull/153643, there may be a BranchOnCond with constant condition in the entry block. Simplify those in removeBranchOnConst. This removes a number of redundant conditional branch from entry blocks. In some cases, it may also make the original scalar loop unreachable, because we know it will never execute. In that case, we need to remove the loop from LoopInfo, because all unreachable blocks may dominate each other, making LoopInfo invalid. In those cases, we can also completely remove the loop, for which I'll share a follow-up patch. Depends on https://github.com/llvm/llvm-project/pull/153643. PR: https://github.com/llvm/llvm-project/pull/154510
63 lines
2.9 KiB
LLVM
63 lines
2.9 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
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; RUN: opt < %s -passes=loop-vectorize,dce,instcombine -force-vector-interleave=1 -force-vector-width=4 -S | FileCheck %s
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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@b = common global [2048 x i32] zeroinitializer, align 16
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@c = common global [2048 x i32] zeroinitializer, align 16
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@a = common global [2048 x i32] zeroinitializer, align 16
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define void @example1(i32 %n) nounwind uwtable ssp {
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; CHECK-LABEL: define void @example1(
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; CHECK-SAME: i32 [[N:%.*]]) #[[ATTR0:[0-9]+]] {
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[N4:%.*]] = shl i32 [[N]], 2
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; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[N4]], -4
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; CHECK-NEXT: [[TMP1:%.*]] = zext i32 [[TMP0]] to i64
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; CHECK-NEXT: br label [[VECTOR_PH:%.*]]
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; CHECK: vector.ph:
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; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
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; CHECK: vector.body:
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; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
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; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds i32, ptr @b, i64 [[INDEX]]
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; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP2]], align 4
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; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr @c, i64 [[INDEX]]
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; CHECK-NEXT: [[WIDE_LOAD1:%.*]] = load <4 x i32>, ptr [[TMP3]], align 4
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; CHECK-NEXT: [[TMP4:%.*]] = add nsw <4 x i32> [[WIDE_LOAD1]], [[WIDE_LOAD]]
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; CHECK-NEXT: [[TMP5:%.*]] = getelementptr inbounds i32, ptr @a, i64 [[INDEX]]
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; CHECK-NEXT: store <4 x i32> [[TMP4]], ptr [[TMP5]], align 4
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; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
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; CHECK-NEXT: [[TMP6:%.*]] = icmp eq i64 [[INDEX]], [[TMP1]]
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; CHECK-NEXT: br i1 [[TMP6]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
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; CHECK: middle.block:
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; CHECK-NEXT: br i1 true, label [[EXIT:%.*]], label [[SCALAR_PH:%.*]]
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; CHECK: scalar.ph:
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; CHECK-NEXT: br label [[LOOP:%.*]]
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; CHECK: loop:
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; CHECK-NEXT: br i1 poison, label [[EXIT]], label [[LOOP]], !llvm.loop [[LOOP3:![0-9]+]]
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; CHECK: exit:
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; CHECK-NEXT: ret void
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;
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entry:
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%n4 = shl i32 %n, 2
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br label %loop
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loop:
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%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %loop ]
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%gep1 = getelementptr inbounds [2048 x i32], ptr @b, i64 0, i64 %indvars.iv
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%load1 = load i32, ptr %gep1, align 4
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%gep2 = getelementptr inbounds [2048 x i32], ptr @c, i64 0, i64 %indvars.iv
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%load2 = load i32, ptr %gep2, align 4
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%add = add nsw i32 %load2, %load1
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%gep3 = getelementptr inbounds [2048 x i32], ptr @a, i64 0, i64 %indvars.iv
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store i32 %add, ptr %gep3, align 4
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%indvars.iv.next = add i64 %indvars.iv, 1
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%lftr.wideiv = trunc i64 %indvars.iv.next to i32
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%exitcond = icmp eq i32 %lftr.wideiv, %n4
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br i1 %exitcond, label %exit, label %loop
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exit:
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ret void
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}
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