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[x64] Improve materialization of certain double constants (i.e. -0.0).

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R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/946423003

Cr-Commit-Position: refs/heads/master@{#26846}
This commit is contained in:
bmeurer 2015-02-25 03:28:39 -08:00 committed by Commit bot
parent 4b5ff0c5e2
commit e1c08bafdd
1 changed files with 30 additions and 11 deletions
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41
src/x64/macro-assembler-x64.cc
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@ -2578,24 +2578,43 @@ void MacroAssembler::Move(XMMRegister dst, uint32_t src) {
if (src == 0) {
xorps(dst, dst);
} else {
movl(kScratchRegister, Immediate(src));
movq(dst, kScratchRegister);
unsigned pop = base::bits::CountPopulation32(src);
DCHECK_NE(0u, pop);
if (pop == 32) {
pcmpeqd(dst, dst);
} else {
movl(kScratchRegister, Immediate(src));
movq(dst, kScratchRegister);
}
}
}
void MacroAssembler::Move(XMMRegister dst, uint64_t src) {
uint32_t lower = static_cast<uint32_t>(src);
uint32_t upper = static_cast<uint32_t>(src >> 32);
if (upper == 0) {
Move(dst, lower);
if (src == 0) {
xorps(dst, dst);
} else {
if (lower == 0) {
Move(dst, upper);
psllq(dst, 32);
unsigned nlz = base::bits::CountLeadingZeros64(src);
unsigned ntz = base::bits::CountTrailingZeros64(src);
unsigned pop = base::bits::CountPopulation64(src);
DCHECK_NE(0u, pop);
if (pop == 64) {
pcmpeqd(dst, dst);
} else if (pop + ntz == 64) {
pcmpeqd(dst, dst);
psllq(dst, ntz);
} else if (pop + nlz == 64) {
pcmpeqd(dst, dst);
psrlq(dst, nlz);
} else {
movq(kScratchRegister, src);
movq(dst, kScratchRegister);
uint32_t lower = static_cast<uint32_t>(src);
uint32_t upper = static_cast<uint32_t>(src >> 32);
if (upper == 0) {
Move(dst, lower);
} else {
movq(kScratchRegister, src);
movq(dst, kScratchRegister);
}
}
}
}