Author: lattner
Date: Thu Feb 14 12:48:56 2008
New Revision: 47128
URL: http://llvm.org/viewvc/llvm-project?rev=47128&view=rev
Log:
Fix a miscompilation from Dan's recent apintification.
Added:
llvm/trunk/test/CodeGen/X86/2008-02-14-BitMiscompile.ll
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=47128&r1=47127&r2=47128&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Thu Feb 14 12:48:56
2008
@@ -1437,12 +1437,10 @@
// We know that the top bits of C-X are clear if X contains less bits
// than C (i.e. no wrap-around can happen). For example, 20-X is
// positive if we can prove that X is >= 0 and < 16.
-
- // sign bit clear
if (CLHS->getAPIntValue().isNonNegative()) {
unsigned NLZ = (CLHS->getAPIntValue()+1).countLeadingZeros();
// NLZ can't be BitWidth with no sign bit
- APInt MaskV = APInt::getHighBitsSet(BitWidth, NLZ);
+ APInt MaskV = APInt::getHighBitsSet(BitWidth, NLZ+1);
ComputeMaskedBits(Op.getOperand(1), MaskV, KnownZero, KnownOne, Depth+1);
// If all of the MaskV bits are known to be zero, then we know the output
Added: llvm/trunk/test/CodeGen/X86/2008-02-14-BitMiscompile.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2008-02-14-BitMiscompile.ll?rev=47128&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2008-02-14-BitMiscompile.ll (added)
+++ llvm/trunk/test/CodeGen/X86/2008-02-14-BitMiscompile.ll Thu Feb 14 12:48:56
2008
@@ -0,0 +1,8 @@
+; RUN: llvm-as < %s | llc -march=x86 | grep and
+define i32 @test(i1 %A) {
+ %B = zext i1 %A to i32 ; <i32> [#uses=1]
+ %C = sub i32 0, %B ; <i32> [#uses=1]
+ %D = and i32 %C, 255 ; <i32> [#uses=1]
+ ret i32 %D
+}
+
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