Implement mul.ll:test11
llvm-svn: 11737
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index f23c10f..a5fcbc9 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -616,12 +616,13 @@
Value *SCIOp0 = SCI->getOperand(0), *SCIOp1 = SCI->getOperand(1);
const Type *SCOpTy = SCIOp0->getType();
- // If the source is X < 0, and X is a signed integer type, convert this
- // multiply into a shift/and combination.
- if (SCI->getOpcode() == Instruction::SetLT &&
- isa<Constant>(SCIOp1) && cast<Constant>(SCIOp1)->isNullValue() &&
- SCOpTy->isInteger() && SCOpTy->isSigned()) {
-
+ // If the source is X < 0 or X <= -1, and X is a signed integer type,
+ // convert this multiply into a shift/and combination.
+ if (SCOpTy->isSigned() && isa<ConstantInt>(SCIOp1) &&
+ ((SCI->getOpcode() == Instruction::SetLT &&
+ cast<Constant>(SCIOp1)->isNullValue()) ||
+ (SCI->getOpcode() == Instruction::SetLE &&
+ cast<ConstantInt>(SCIOp1)->isAllOnesValue()))) {
// Shift the X value right to turn it into "all signbits".
Constant *Amt = ConstantUInt::get(Type::UByteTy,
SCOpTy->getPrimitiveSize()*8-1);