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Fix a missing peephole optimization in ia32 code exposed with Kevin's

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change.

Review URL: http://codereview.chromium.org/7117

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@491 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
iposva@chromium.org 2008-10-13 20:15:17 +00:00
parent dcf8ef2842
commit 49c5ed0029
1 changed files with 17 additions and 0 deletions
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17
src/assembler-ia32.cc
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@ -720,6 +720,23 @@ void Assembler::add(Register dst, const Operand& src) {
void Assembler::add(const Operand& dst, const Immediate& x) {
ASSERT(reloc_info_writer.last_pc() != NULL);
if (FLAG_push_pop_elimination && (reloc_info_writer.last_pc() <= last_pc_)) {
byte instr = last_pc_[0];
if ((instr & 0xf8) == 0x50) {
// Last instruction was a push. Check whether this is a pop without a
// result.
if ((dst.is_reg(esp)) &&
(x.x_ == kPointerSize) && (x.rmode_ == RelocInfo::NONE)) {
pc_ = last_pc_;
last_pc_ = NULL;
if (FLAG_print_push_pop_elimination) {
PrintF("%d push/pop(noreg) eliminated\n", pc_offset());
}
return;
}
}
}
EnsureSpace ensure_space(this);
last_pc_ = pc_;
emit_arith(0, dst, x);