c752bb9203
When reviewing another change, I noticed that we were failing to infer samsign for two cases: 1) an unsigned comparison, and 2) when both arguments were known negative. Using CVP and InstCombine as a reference, we need to be careful to not allow eq/ne comparisons. I'm a bit unclear on the why of that, and for now am going with the low risk change. I may return to investigate that in a follow up. Compile time results look like noise to me, see: https://llvm-compile-time-tracker.com/compare.php?from=49a978712893fcf9e5f40ac488315d029cf15d3d&to=2ddb263604fd7d538e09dc1f805ebc30eb3ffab0&stat=instructions:u
36 lines
1.3 KiB
LLVM
36 lines
1.3 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -passes=indvars -S | FileCheck %s
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@Y = global [400 x i16] zeroinitializer, align 1
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define i16 @foo() {
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; CHECK-LABEL: @foo(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[FOR_BODY:%.*]]
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; CHECK: for.body:
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; CHECK-NEXT: [[I:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
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; CHECK-NEXT: [[ARRAYIDX:%.*]] = getelementptr inbounds [400 x i16], ptr @Y, i16 0, i16 [[I]]
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; CHECK-NEXT: store i16 0, ptr [[ARRAYIDX]], align 1
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; CHECK-NEXT: [[INC]] = add nuw nsw i16 [[I]], 1
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; CHECK-NEXT: [[CMP:%.*]] = icmp samesign ult i16 [[INC]], 400
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; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_END:%.*]]
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; CHECK: for.end:
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; CHECK-NEXT: ret i16 400
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;
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entry:
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br label %for.body
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for.body: ; preds = %entry, %for.body
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%i = phi i16 [ 0, %entry ], [ %inc, %for.body ]
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%arrayidx = getelementptr inbounds [400 x i16], ptr @Y, i16 0, i16 %i
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store i16 0, ptr %arrayidx, align 1
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%inc = add nuw nsw i16 %i, 1
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%cmp = icmp ult i16 %inc, 400
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br i1 %cmp, label %for.body, label %for.end
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for.end: ; preds = %for.body
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%inc.lcssa = phi i16 [ %inc, %for.body ]
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ret i16 %inc.lcssa
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}
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