diff options
| author | Chris Lattner <sabre@nondot.org> | 2011-04-18 07:00:40 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-04-18 07:00:40 +0000 |
| commit | f051c1a29dd040b4b5ca0c5696d47a9058f87481 (patch) | |
| tree | f55cd7f6174aa97971946740fd80743f45bde6f7 /lib/CodeGen | |
| parent | 090ca9108b35a60e8b97b67987d00cf47a383dba (diff) | |
while we're at it, handle 'sdiv exact' of a power of 2 also,
this fixes a few rejects on c++ iterator loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129694 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/FastISel.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp index d3a721f875..76e9a7cac2 100644 --- a/lib/CodeGen/SelectionDAG/FastISel.cpp +++ b/lib/CodeGen/SelectionDAG/FastISel.cpp @@ -360,6 +360,14 @@ bool FastISel::SelectBinaryOp(const User *I, unsigned ISDOpcode) { if (ConstantInt *CI = dyn_cast<ConstantInt>(I->getOperand(1))) { uint64_t Imm = CI->getZExtValue(); + // Transform "sdiv exact X, 8" -> "sra X, 3". + if (ISDOpcode == ISD::SDIV && isa<BinaryOperator>(I) && + cast<BinaryOperator>(I)->isExact() && + isPowerOf2_64(Imm)) { + Imm = Log2_64(Imm); + ISDOpcode = ISD::SRA; + } + unsigned ResultReg = FastEmit_ri_(VT.getSimpleVT(), ISDOpcode, Op0, Op0IsKill, Imm, VT.getSimpleVT()); if (ResultReg == 0) return false; |