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| author | Rafael Espindola <rafael.espindola@gmail.com> | 2014-05-30 15:00:45 +0000 |
|---|---|---|
| committer | Rafael Espindola <rafael.espindola@gmail.com> | 2014-05-30 15:00:45 +0000 |
| commit | 6319c0c5203450e9d9a79cc6d57764b97d814da2 (patch) | |
| tree | 85cd42525ea8cf34eab3fcc3ac6e31c95aaa750c | |
| parent | 3a45d4c62136a0eb7c433a0e6435e8734aa28333 (diff) | |
| download | llvm-6319c0c5203450e9d9a79cc6d57764b97d814da2.tar.gz llvm-6319c0c5203450e9d9a79cc6d57764b97d814da2.tar.bz2 llvm-6319c0c5203450e9d9a79cc6d57764b97d814da2.tar.xz | |
[pr19636] Fix known bit computation in urem instruction with power of two.
Patch by Andrey Kuharev.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209902 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 7 | ||||
| -rw-r--r-- | test/CodeGen/X86/computeKnownBits_urem.ll | 14 |
2 files changed, 19 insertions, 2 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 51ae11dea2..65a3f0a94b 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -2185,8 +2185,11 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero, const APInt &RA = Rem->getAPIntValue(); if (RA.isPowerOf2()) { APInt LowBits = (RA - 1); - KnownZero |= ~LowBits; - computeKnownBits(Op.getOperand(0), KnownZero, KnownOne,Depth+1); + computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth + 1); + + // The upper bits are all zero, the lower ones are unchanged. + KnownZero = KnownZero2 | ~LowBits; + KnownOne = KnownOne2 & LowBits; break; } } diff --git a/test/CodeGen/X86/computeKnownBits_urem.ll b/test/CodeGen/X86/computeKnownBits_urem.ll new file mode 100644 index 0000000000..9902e6f259 --- /dev/null +++ b/test/CodeGen/X86/computeKnownBits_urem.ll @@ -0,0 +1,14 @@ +; RUN: llc -mtriple=x86_64-linux < %s | FileCheck %s +define i32 @main() #0 { +entry: + %a = alloca i32, align 4 + store i32 1, i32* %a, align 4 + %0 = load i32* %a, align 4 + %or = or i32 1, %0 + %and = and i32 1, %or + %rem = urem i32 %and, 1 + %add = add i32 %rem, 1 + ret i32 %add +} +; CHECK: $1, %eax +; CHECK-NEXT: retq |