diff options
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineSelect.cpp | 13 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/select.ll | 36 |
2 files changed, 45 insertions, 4 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp index 59502fb..7581dbe 100644 --- a/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -662,7 +662,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, ConstantInt *FalseVal, InstCombiner::BuilderTy *Builder) { const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition()); - if (!IC || !IC->isEquality()) + if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy()) return 0; if (!match(IC->getOperand(1), m_Zero())) @@ -670,8 +670,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, ConstantInt *AndRHS; Value *LHS = IC->getOperand(0); - if (LHS->getType() != SI.getType() || - !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) + if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS)))) return 0; // If both select arms are non-zero see if we have a select of the form @@ -705,7 +704,13 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal, unsigned ValZeros = ValC->getValue().logBase2(); unsigned AndZeros = AndRHS->getValue().logBase2(); - Value *V = LHS; + // If types don't match we can still convert the select by introducing a zext + // or a trunc of the 'and'. The trunc case requires that all of the truncated + // bits are zero, we can figure that out by looking at the 'and' mask. + if (AndZeros >= ValC->getBitWidth()) + return 0; + + Value *V = Builder->CreateZExtOrTrunc(LHS, SI.getType()); if (ValZeros > AndZeros) V = Builder->CreateShl(V, ValZeros - AndZeros); else if (ValZeros < AndZeros) diff --git a/test/Transforms/InstCombine/select.ll b/test/Transforms/InstCombine/select.ll index c72a6f7..5bf9423 100644 --- a/test/Transforms/InstCombine/select.ll +++ b/test/Transforms/InstCombine/select.ll @@ -985,3 +985,39 @@ define i32 @select_icmp_ne_0_and_8_or_1073741824(i8 %x, i32 %y) { %select = select i1 %cmp, i32 %y, i32 %or ret i32 %select } + +define i32 @test65(i64 %x) { + %1 = and i64 %x, 16 + %2 = icmp ne i64 %1, 0 + %3 = select i1 %2, i32 40, i32 42 + ret i32 %3 + +; CHECK: @test65 +; CHECK: and i64 %x, 16 +; CHECK: trunc i64 %1 to i32 +; CHECK: lshr exact i32 %2, 3 +; CHECK: xor i32 %3, 42 +} + +define i32 @test66(i64 %x) { + %1 = and i64 %x, 4294967296 + %2 = icmp ne i64 %1, 0 + %3 = select i1 %2, i32 40, i32 42 + ret i32 %3 + +; CHECK: @test66 +; CHECK: select +} + +define i32 @test67(i16 %x) { + %1 = and i16 %x, 4 + %2 = icmp ne i16 %1, 0 + %3 = select i1 %2, i32 40, i32 42 + ret i32 %3 + +; CHECK: @test67 +; CHECK: and i16 %x, 4 +; CHECK: zext i16 %1 to i32 +; CHECK: lshr exact i32 %2, 1 +; CHECK: xor i32 %3, 42 +} |