Revision: 25146
Author: [email protected]
Date: Wed Nov 5 11:50:49 2014 UTC
Log: ARM: optimize inlined doubles
Use 'vmov Dn[x], ip' instead of 'vmov Sn, ip' to load double immediates.
This patch is only useful for Turbofan as Crankshaft loads double
immediates from the constant pool.
This give a little improvement on asm.js benchmarks
[email protected], [email protected]
BUG=
Review URL: https://codereview.chromium.org/704543002
https://code.google.com/p/v8/source/detail?r=25146
Modified:
/branches/bleeding_edge/src/arm/assembler-arm.cc
=======================================
--- /branches/bleeding_edge/src/arm/assembler-arm.cc Thu Oct 30 11:00:47
2014 UTC
+++ /branches/bleeding_edge/src/arm/assembler-arm.cc Wed Nov 5 11:50:49
2014 UTC
@@ -2545,27 +2545,20 @@
uint32_t lo, hi;
DoubleAsTwoUInt32(imm, &lo, &hi);
- if (scratch.is(no_reg)) {
- if (dst.code() < 16) {
- const LowDwVfpRegister loc =
LowDwVfpRegister::from_code(dst.code());
- // Move the low part of the double into the lower of the
corresponsing S
- // registers of D register dst.
- mov(ip, Operand(lo));
- vmov(loc.low(), ip);
-
- // Move the high part of the double into the higher of the
- // corresponsing S registers of D register dst.
- mov(ip, Operand(hi));
- vmov(loc.high(), ip);
+ if (lo == hi) {
+ // Move the low and high parts of the double to a D register in one
+ // instruction.
+ mov(ip, Operand(lo));
+ vmov(dst, ip, ip);
+ } else if (scratch.is(no_reg)) {
+ mov(ip, Operand(lo));
+ vmov(dst, VmovIndexLo, ip);
+ if ((lo & 0xffff) == (hi & 0xffff)) {
+ movt(ip, hi >> 16);
} else {
- // D16-D31 does not have S registers, so move the low and high
parts
- // directly to the D register using vmov.32.
- // Note: This may be slower, so we only do this when we have to.
- mov(ip, Operand(lo));
- vmov(dst, VmovIndexLo, ip);
mov(ip, Operand(hi));
- vmov(dst, VmovIndexHi, ip);
}
+ vmov(dst, VmovIndexHi, ip);
} else {
// Move the low and high parts of the double to a D register in one
// instruction.
--
--
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