abe3c5ac19
GVNSink used to order instructions based on their pointer values and was prone to non-determinism because of that. This patch ensures all the values stored are using a deterministic order. I have also added a verfier(`ModelledPHI::verifyModelledPHI`) to assert when ordering isn't preserved. Additionally, I have added a test case (mirror graph image of an existing test) that would have failed before this patch. Fixes: #77852
57 lines
1.2 KiB
LLVM
57 lines
1.2 KiB
LLVM
; RUN: opt -S < %s -passes=gvn-sink | FileCheck %s
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declare void @llvm.sideeffect()
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; GVN sinking across a @llvm.sideeffect.
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; CHECK-LABEL: scalarsSinking
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; CHECK-NOT: fmul
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; CHECK: = phi
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; CHECK: = fmul
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define float @scalarsSinking(float %d, float %m, float %a, i1 %cmp) {
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entry:
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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call void @llvm.sideeffect()
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%sub = fsub float %m, %a
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%mul0 = fmul float %sub, %d
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br label %if.end
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if.else:
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%add = fadd float %m, %a
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%mul1 = fmul float %add, %d
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br label %if.end
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if.end:
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%phi = phi float [ %mul0, %if.then ], [ %mul1, %if.else ]
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ret float %phi
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}
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; CHECK-LABEL: scalarsSinkingReverse
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; CHECK-NOT: fmul
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; CHECK: = phi
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; CHECK: = fmul
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define float @scalarsSinkingReverse(float %d, float %m, float %a, i1 %cmp) {
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; This test is just a reverse(graph mirror) of the test
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; above to ensure GVNSink doesn't depend on the order of branches.
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entry:
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br i1 %cmp, label %if.then, label %if.else
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if.then:
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%add = fadd float %m, %a
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%mul1 = fmul float %add, %d
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br label %if.end
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if.else:
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call void @llvm.sideeffect()
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%sub = fsub float %m, %a
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%mul0 = fmul float %sub, %d
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br label %if.end
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if.end:
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%phi = phi float [ %mul1, %if.then ], [ %mul0, %if.else ]
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ret float %phi
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}
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