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Fix a typo in ValueTracking that's causing instcombine to delete needed shift instructions. 

llvm-svn: 98416
This commit is contained in:
Evan Cheng 2010-03-13 02:20:29 +00:00
parent b7aa9527ef
commit 2a65429671
2 changed files with 21 additions and 1 deletions
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2
llvm/lib/Analysis/ValueTracking.cpp
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@ -779,7 +779,7 @@ unsigned llvm::ComputeNumSignBits(Value *V, const TargetData *TD,
for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
if (Tmp == 1) return Tmp;
Tmp = std::min(Tmp,
ComputeNumSignBits(PN->getIncomingValue(1), TD, Depth+1));
ComputeNumSignBits(PN->getIncomingValue(i), TD, Depth+1));
}
return Tmp;
}

20
llvm/test/Transforms/InstCombine/shift-sra.ll
View File

@ -56,3 +56,23 @@ C:
; CHECK: %P = phi i64
; CHECK-NEXT: ret i64 %P
}
; rdar://7732987
define i32 @test5(i32 %Y) {
br i1 undef, label %A, label %C
A:
br i1 undef, label %B, label %D
B:
br label %D
C:
br i1 undef, label %D, label %E
D:
%P = phi i32 [0, %A], [0, %B], [%Y, %C]
%S = ashr i32 %P, 16
ret i32 %S
; CHECK: @test5
; CHECK: %P = phi i32
; CHECK-NEXT: ashr i32 %P, 16
E:
ret i32 0
}