75b33d6bd5
This is the bugfix to the miscompile mentioned in https://reviews.llvm.org/D132055#3814831. The IR that reproduced the bug is added as the test case in this patch. What this patch does is that, during legality phase instead of checking the phi nodes only in `InnerLoop` and `OuterLoop`, we check phi nodes in all subloops of the `OuterLoop`. Suppose if the loop nest is triply nested, and `InnerLoop` and `OuterLoop` is the middle loop and the outermost loop respectively, we'll check phi nodes in the innermost loop as well, in addition to the ones in the middle and outermost loops. Reviewed By: Meinersbur, #loopoptwg Differential Revision: https://reviews.llvm.org/D134930
78 lines
3.5 KiB
LLVM
78 lines
3.5 KiB
LLVM
; RUN: opt < %s -loop-interchange -cache-line-size=4 -pass-remarks-missed='loop-interchange' -pass-remarks-output=%t -S \
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; RUN: -verify-dom-info -verify-loop-info -verify-loop-lcssa
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; RUN: FileCheck --input-file=%t --check-prefix=REMARKS %s
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@b = external global [512 x [4 x i32]]
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@c = global [2 x [4 x i32]] zeroinitializer, align 1
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; Check that the outermost and the middle loops are not interchanged since
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; the innermost loop has a reduction operation which is however not in a form
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; that loop interchange can handle. Interchanging the outermost and the
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; middle loops would intervene with the reduction and cause miscompile.
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; REMARKS: --- !Missed
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; REMARKS-NEXT: Pass: loop-interchange
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; REMARKS-NEXT: Name: UnsupportedPHIInner
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; REMARKS-NEXT: Function: test7
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; REMARKS: --- !Missed
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; REMARKS-NEXT: Pass: loop-interchange
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; REMARKS-NEXT: Name: UnsupportedPHIInner
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; REMARKS-NEXT: Function: test7
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define i32 @test7() {
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entry:
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br label %for.cond1.preheader.i
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for.cond1.preheader.i: ; preds = %for.inc19.i, %entry
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%i.011.i = phi i16 [ 0, %entry ], [ %inc20.i, %for.inc19.i ]
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br label %for.cond4.preheader.i
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for.cond4.preheader.i: ; preds = %middle.block, %for.cond1.preheader.i
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%j.010.i = phi i16 [ 0, %for.cond1.preheader.i ], [ %inc17.i, %middle.block ]
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%arrayidx14.i = getelementptr inbounds [2 x [4 x i32]], ptr @c, i16 0, i16 %i.011.i, i16 %j.010.i
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%arrayidx14.promoted.i = load i32, ptr %arrayidx14.i, align 1
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%0 = insertelement <4 x i32> <i32 poison, i32 0, i32 0, i32 0>, i32 %arrayidx14.promoted.i, i64 0
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br label %vector.body
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vector.body: ; preds = %vector.body, %for.cond4.preheader.i
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%index = phi i16 [ 0, %for.cond4.preheader.i ], [ %index.next, %vector.body ]
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%vec.phi = phi <4 x i32> [ %0, %for.cond4.preheader.i ], [ %16, %vector.body ]
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%1 = or i16 %index, 1
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%2 = or i16 %index, 2
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%3 = or i16 %index, 3
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%4 = getelementptr inbounds [512 x [4 x i32]], ptr @b, i16 0, i16 %index, i16 %j.010.i
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%5 = getelementptr inbounds [512 x [4 x i32]], ptr @b, i16 0, i16 %1, i16 %j.010.i
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%6 = getelementptr inbounds [512 x [4 x i32]], ptr @b, i16 0, i16 %2, i16 %j.010.i
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%7 = getelementptr inbounds [512 x [4 x i32]], ptr @b, i16 0, i16 %3, i16 %j.010.i
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%8 = load i32, ptr %4, align 1
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%9 = load i32, ptr %5, align 1
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%10 = load i32, ptr %6, align 1
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%11 = load i32, ptr %7, align 1
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%12 = insertelement <4 x i32> poison, i32 %8, i64 0
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%13 = insertelement <4 x i32> %12, i32 %9, i64 1
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%14 = insertelement <4 x i32> %13, i32 %10, i64 2
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%15 = insertelement <4 x i32> %14, i32 %11, i64 3
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%16 = add <4 x i32> %15, %vec.phi
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%index.next = add nuw i16 %index, 4
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%17 = icmp eq i16 %index.next, 512
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br i1 %17, label %middle.block, label %vector.body
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middle.block: ; preds = %vector.body
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%18 = tail call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> %16)
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store i32 %18, ptr %arrayidx14.i, align 1
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%inc17.i = add nuw nsw i16 %j.010.i, 1
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%exitcond12.not.i = icmp eq i16 %inc17.i, 4
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br i1 %exitcond12.not.i, label %for.inc19.i, label %for.cond4.preheader.i
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for.inc19.i: ; preds = %middle.block
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%inc20.i = add nuw nsw i16 %i.011.i, 1
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%exitcond13.not.i = icmp eq i16 %inc20.i, 2
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br i1 %exitcond13.not.i, label %test.exit, label %for.cond1.preheader.i
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test.exit: ; preds = %for.inc19.i
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%19 = load i32, ptr @c, align 1
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ret i32 %19
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}
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declare i32 @llvm.vector.reduce.add.v4i32(<4 x i32>)
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