diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp | 12 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll | 10 |
2 files changed, 15 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp index edad6a45121..f82a5b1806c 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -3314,7 +3314,7 @@ foldShiftIntoShiftInAnotherHandOfAndInICmp(ICmpInst &I, const SimplifyQuery SQ, // Pick the single-use shift as XShift. Value *XShift, *YShift; if (!match(I.getOperand(0), - m_c_And(m_OneUse(m_CombineAnd(m_AnyLogicalShift, m_Value(XShift))), + m_c_And(m_CombineAnd(m_AnyLogicalShift, m_Value(XShift)), m_CombineAnd(m_AnyLogicalShift, m_Value(YShift))))) return nullptr; @@ -3332,6 +3332,16 @@ foldShiftIntoShiftInAnotherHandOfAndInICmp(ICmpInst &I, const SimplifyQuery SQ, match(XShift, m_BinOp(m_Value(X), m_Value(XShAmt))); match(YShift, m_BinOp(m_Value(Y), m_Value(YShAmt))); + // If one of the values being shifted is a constant, then we will end with + // and+icmp, and shift instr will be constant-folded. If they are not, + // however, we will need to ensure that we won't increase instruction count. + if (!isa<Constant>(X) && !isa<Constant>(Y)) { + // At least one of the hands of the 'and' should be one-use shift. + if (!match(I.getOperand(0), + m_c_And(m_OneUse(m_AnyLogicalShift), m_Value()))) + return nullptr; + } + // Can we fold (XShAmt+YShAmt) ? Value *NewShAmt = SimplifyBinOp(Instruction::BinaryOps::Add, XShAmt, YShAmt, SQ.getWithInstruction(&I)); diff --git a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll index 18e8cfadfeb..55d268b9b77 100644 --- a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll +++ b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll @@ -534,9 +534,9 @@ define i1 @t32_shift_of_const_oneuse0(i32 %x, i32 %y, i32 %len) { ; CHECK-NEXT: call void @use32(i32 [[T2]]) ; CHECK-NEXT: [[T3:%.*]] = shl i32 [[Y:%.*]], [[T2]] ; CHECK-NEXT: call void @use32(i32 [[T3]]) -; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3]] -; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 -; CHECK-NEXT: ret i1 [[T5]] +; CHECK-NEXT: [[TMP1:%.*]] = and i32 [[Y]], 1 +; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 0 +; CHECK-NEXT: ret i1 [[TMP2]] ; %t0 = sub i32 32, %len call void @use32(i32 %t0) @@ -561,9 +561,7 @@ define i1 @t33_shift_of_const_oneuse1(i32 %x, i32 %y, i32 %len) { ; CHECK-NEXT: call void @use32(i32 [[T2]]) ; CHECK-NEXT: [[T3:%.*]] = shl i32 -52543054, [[T2]] ; CHECK-NEXT: call void @use32(i32 [[T3]]) -; CHECK-NEXT: [[T4:%.*]] = and i32 [[T1]], [[T3]] -; CHECK-NEXT: [[T5:%.*]] = icmp ne i32 [[T4]], 0 -; CHECK-NEXT: ret i1 [[T5]] +; CHECK-NEXT: ret i1 false ; %t0 = sub i32 32, %len call void @use32(i32 %t0) |
