diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 29 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/imul.ll | 45 |
2 files changed, 3 insertions, 71 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 1de926bf41f..b1b7f5d4586 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -24738,11 +24738,9 @@ static SDValue PerformMulCombine(SDNode *N, SelectionDAG &DAG, MulAmt1 = 3; MulAmt2 = MulAmt / 3; } - - SDLoc DL(N); - SDValue NewMul; if (MulAmt2 && (isPowerOf2_64(MulAmt2) || MulAmt2 == 3 || MulAmt2 == 5 || MulAmt2 == 9)){ + SDLoc DL(N); if (isPowerOf2_64(MulAmt2) && !(N->hasOneUse() && N->use_begin()->getOpcode() == ISD::ADD)) @@ -24751,6 +24749,7 @@ static SDValue PerformMulCombine(SDNode *N, SelectionDAG &DAG, // is an add. std::swap(MulAmt1, MulAmt2); + SDValue NewMul; if (isPowerOf2_64(MulAmt1)) NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), DAG.getConstant(Log2_64(MulAmt1), DL, MVT::i8)); @@ -24764,32 +24763,10 @@ static SDValue PerformMulCombine(SDNode *N, SelectionDAG &DAG, else NewMul = DAG.getNode(X86ISD::MUL_IMM, DL, VT, NewMul, DAG.getConstant(MulAmt2, DL, VT)); - } - - if (!NewMul) { - uint64_t MaxVal = VT == MVT::i64 ? UINT64_MAX : UINT32_MAX; - assert(MulAmt != 0 && MulAmt != MaxVal && - "Both cases that could cause potential " - "overflows should have already been handled."); - if (isPowerOf2_64(MulAmt - 1)) - // (mul x, 2^N + 1) => (add (shl x, N), x) - NewMul = DAG.getNode(ISD::ADD, DL, VT, N->getOperand(0), - DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(Log2_64(MulAmt - 1), DL, - MVT::i8))); - else if (isPowerOf2_64(MulAmt + 1)) - // (mul x, 2^N - 1) => (sub (shl x, N), x) - NewMul = DAG.getNode(ISD::SUB, DL, VT, DAG.getNode(ISD::SHL, DL, VT, - N->getOperand(0), - DAG.getConstant(Log2_64(MulAmt + 1), - DL, MVT::i8)), N->getOperand(0)); - } - - if (NewMul) // Do not add new nodes to DAG combiner worklist. DCI.CombineTo(N, NewMul, false); - + } return SDValue(); } diff --git a/llvm/test/CodeGen/X86/imul.ll b/llvm/test/CodeGen/X86/imul.ll index 9d4d19332db..99a4690a009 100644 --- a/llvm/test/CodeGen/X86/imul.ll +++ b/llvm/test/CodeGen/X86/imul.ll @@ -126,48 +126,3 @@ define i32 @mul40_32_minsize(i32 %A) minsize { %mul = mul i32 %A, 40 ret i32 %mul } - -define i32 @mul33_32(i32 %A) { -; X64-LABEL: mul33_32: -; X64: shll -; X64-NEXT: leal -; X86-LABEL: mul33_32: -; X86: shll -; X86-NEXT: addl - %mul = mul i32 %A, 33 - ret i32 %mul -} - -define i32 @mul31_32(i32 %A) { -; X64-LABEL: mul31_32: -; X64: shll -; X64-NEXT: subl -; X86-LABEL: mul31_32: -; X86: shll -; X86-NEXT: subl - %mul = mul i32 %A, 31 - ret i32 %mul -} - -define i32 @mul0_32(i32 %A) { -; X64-LABEL: mul0_32: -; X64: xorl %eax, %eax - %mul = mul i32 %A, 0 - ret i32 %mul -} - -define i32 @mul4294967295_32(i32 %A) { -; X64-LABEL: mul4294967295_32: -; X64: negl %edi -; X64-NEXT: movl %edi, %eax - %mul = mul i32 %A, 4294967295 - ret i32 %mul -} - -define i64 @mul18446744073709551615_64(i64 %A) { -; X64-LABEL: mul18446744073709551615_64: -; X64: negq %rdi -; X64-NEXT: movq %rdi, %rax - %mul = mul i64 %A, 18446744073709551615 - ret i64 %mul -} |
