diff options
| author | Chris Lattner <sabre@nondot.org> | 2004-02-03 18:54:04 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2004-02-03 18:54:04 +0000 |
| commit | 9f08a92e6cbe18446eb36e2dc0a41b44910e6621 (patch) | |
| tree | 40a14aceaba3ed744bb752d92e30de8eab88e1b6 | |
| parent | acc00bc6095c4362c8a780091cd67fcc32510592 (diff) | |
Generate ftst instructions for comparison against zero
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11098 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Target/X86/InstSelectSimple.cpp | 9 | ||||
| -rw-r--r-- | lib/Target/X86/X86ISelSimple.cpp | 9 |
2 files changed, 18 insertions, 0 deletions
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp index abfcad1566..45df82906b 100644 --- a/lib/Target/X86/InstSelectSimple.cpp +++ b/lib/Target/X86/InstSelectSimple.cpp @@ -702,6 +702,15 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1, return OpNum; } + // Special case handling of comparison against +/- 0.0 + if (ConstantFP *CFP = dyn_cast<ConstantFP>(Op1)) + if (CFP->isExactlyValue(+0.0) || CFP->isExactlyValue(-0.0)) { + BMI(MBB, IP, X86::FTST, 1).addReg(Op0r); + BMI(MBB, IP, X86::FNSTSWr8, 0); + BMI(MBB, IP, X86::SAHF, 1); + return OpNum; + } + unsigned Op1r = getReg(Op1, MBB, IP); switch (Class) { default: assert(0 && "Unknown type class!"); diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp index abfcad1566..45df82906b 100644 --- a/lib/Target/X86/X86ISelSimple.cpp +++ b/lib/Target/X86/X86ISelSimple.cpp @@ -702,6 +702,15 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1, return OpNum; } + // Special case handling of comparison against +/- 0.0 + if (ConstantFP *CFP = dyn_cast<ConstantFP>(Op1)) + if (CFP->isExactlyValue(+0.0) || CFP->isExactlyValue(-0.0)) { + BMI(MBB, IP, X86::FTST, 1).addReg(Op0r); + BMI(MBB, IP, X86::FNSTSWr8, 0); + BMI(MBB, IP, X86::SAHF, 1); + return OpNum; + } + unsigned Op1r = getReg(Op1, MBB, IP); switch (Class) { default: assert(0 && "Unknown type class!"); |