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| author | Chris Lattner <sabre@nondot.org> | 2004-05-07 19:55:55 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2004-05-07 19:55:55 +0000 |
| commit | 260195d2b1a2a3be54d932ccd8da45346bec5676 (patch) | |
| tree | 886b7b00decba771065d42e937db669d53f7b122 /lib/Target | |
| parent | add68af0314949857697b8dc2ac145dca842c7a1 (diff) | |
| download | external_llvm-260195d2b1a2a3be54d932ccd8da45346bec5676.zip external_llvm-260195d2b1a2a3be54d932ccd8da45346bec5676.tar.gz external_llvm-260195d2b1a2a3be54d932ccd8da45346bec5676.tar.bz2 | |
Make comparisons against the null pointer as efficient as integer comparisons
against zero. In particular, don't emit:
mov %ESI, 0
cmp %ECX, %ESI
instead, emit:
test %ECX, %ECX
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13407 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Target')
| -rw-r--r-- | lib/Target/X86/InstSelectSimple.cpp | 9 | ||||
| -rw-r--r-- | lib/Target/X86/X86ISelSimple.cpp | 9 |
2 files changed, 16 insertions, 2 deletions
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp index da2175b..4597a82 100644 --- a/lib/Target/X86/InstSelectSimple.cpp +++ b/lib/Target/X86/InstSelectSimple.cpp @@ -829,7 +829,14 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1, unsigned Op0r = getReg(Op0, MBB, IP); // Special case handling of: cmp R, i - if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { + if (isa<ConstantPointerNull>(Op1)) { + if (OpNum < 2) // seteq/setne -> test + BuildMI(*MBB, IP, X86::TEST32rr, 2).addReg(Op0r).addReg(Op0r); + else + BuildMI(*MBB, IP, X86::CMP32ri, 2).addReg(Op0r).addImm(0); + return OpNum; + + } else if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Class == cByte || Class == cShort || Class == cInt) { unsigned Op1v = CI->getRawValue(); diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp index da2175b..4597a82 100644 --- a/lib/Target/X86/X86ISelSimple.cpp +++ b/lib/Target/X86/X86ISelSimple.cpp @@ -829,7 +829,14 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1, unsigned Op0r = getReg(Op0, MBB, IP); // Special case handling of: cmp R, i - if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { + if (isa<ConstantPointerNull>(Op1)) { + if (OpNum < 2) // seteq/setne -> test + BuildMI(*MBB, IP, X86::TEST32rr, 2).addReg(Op0r).addReg(Op0r); + else + BuildMI(*MBB, IP, X86::CMP32ri, 2).addReg(Op0r).addImm(0); + return OpNum; + + } else if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { if (Class == cByte || Class == cShort || Class == cInt) { unsigned Op1v = CI->getRawValue(); |