diff options
| author | Josh Bleecher Snyder <josharian@gmail.com> | 2014-12-22 15:12:28 -0800 |
|---|---|---|
| committer | Josh Bleecher Snyder <josharian@gmail.com> | 2015-01-07 22:26:55 +0000 |
| commit | 43c87aa481f4e10777b05bf05edd15403853348f (patch) | |
| tree | 0c9597c937977318d1be79cfd3cb2f9ce5f73969 /src/liblink/obj6.c | |
| parent | d5e4c4061b019a36ed3ac954c98f6535b7e78189 (diff) | |
| download | go-43c87aa481f4e10777b05bf05edd15403853348f.tar.xz | |
cmd/6g, cmd/8g, liblink: improve handling of float constants
* Enable basic constant propagation for floats.
The constant propagation is still not as aggressive as it could be.
* Implement MOVSS $(0), Xx and MOVSD $(0), Xx as XORPS Xx, Xx.
Sample code:
func f32() float32 {
var f float32
return f
}
func f64() float64 {
var f float64
return f
}
Before:
"".f32 t=1 size=32 value=0 args=0x8 locals=0x0
0x0000 00000 (demo.go:3) TEXT "".f32+0(SB),4,$0-8
0x0000 00000 (demo.go:3) FUNCDATA $0,gclocals·a7a3692b8e27e823add69ec4239ba55f+0(SB)
0x0000 00000 (demo.go:3) FUNCDATA $1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
0x0000 00000 (demo.go:3) MOVSS $f32.00000000+0(SB),X0
0x0008 00008 (demo.go:4) MOVSS $f32.00000000+0(SB),X0
0x0010 00016 (demo.go:5) MOVSS X0,"".~r0+8(FP)
0x0016 00022 (demo.go:5) RET ,
"".f64 t=1 size=32 value=0 args=0x8 locals=0x0
0x0000 00000 (demo.go:8) TEXT "".f64+0(SB),4,$0-8
0x0000 00000 (demo.go:8) FUNCDATA $0,gclocals·a7a3692b8e27e823add69ec4239ba55f+0(SB)
0x0000 00000 (demo.go:8) FUNCDATA $1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
0x0000 00000 (demo.go:8) MOVSD $f64.0000000000000000+0(SB),X0
0x0008 00008 (demo.go:9) MOVSD $f64.0000000000000000+0(SB),X0
0x0010 00016 (demo.go:10) MOVSD X0,"".~r0+8(FP)
0x0016 00022 (demo.go:10) RET ,
After:
"".f32 t=1 size=16 value=0 args=0x8 locals=0x0
0x0000 00000 (demo.go:3) TEXT "".f32+0(SB),4,$0-8
0x0000 00000 (demo.go:3) FUNCDATA $0,gclocals·a7a3692b8e27e823add69ec4239ba55f+0(SB)
0x0000 00000 (demo.go:3) FUNCDATA $1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
0x0000 00000 (demo.go:3) XORPS X0,X0
0x0003 00003 (demo.go:5) MOVSS X0,"".~r0+8(FP)
0x0009 00009 (demo.go:5) RET ,
"".f64 t=1 size=16 value=0 args=0x8 locals=0x0
0x0000 00000 (demo.go:8) TEXT "".f64+0(SB),4,$0-8
0x0000 00000 (demo.go:8) FUNCDATA $0,gclocals·a7a3692b8e27e823add69ec4239ba55f+0(SB)
0x0000 00000 (demo.go:8) FUNCDATA $1,gclocals·3280bececceccd33cb74587feedb1f9f+0(SB)
0x0000 00000 (demo.go:8) XORPS X0,X0
0x0003 00003 (demo.go:10) MOVSD X0,"".~r0+8(FP)
0x0009 00009 (demo.go:10) RET ,
Change-Id: Ie9eb65e324af4f664153d0a7cd22bb16b0fba16d
Reviewed-on: https://go-review.googlesource.com/2053
Reviewed-by: Russ Cox <rsc@golang.org>
Diffstat (limited to 'src/liblink/obj6.c')
| -rw-r--r-- | src/liblink/obj6.c | 28 |
1 files changed, 26 insertions, 2 deletions
diff --git a/src/liblink/obj6.c b/src/liblink/obj6.c index 2acfd2f70d..a8a84f72ce 100644 --- a/src/liblink/obj6.c +++ b/src/liblink/obj6.c @@ -241,6 +241,19 @@ progedit(Link *ctxt, Prog *p) // Rewrite float constants to values stored in memory. switch(p->as) { + case AMOVSS: + // Convert AMOVSS $(0), Xx to AXORPS Xx, Xx + if(p->from.type == D_FCONST) + if(p->from.u.dval == 0) + if(p->to.type >= D_X0) + if(p->to.type <= D_X15) { + p->as = AXORPS; + p->from.type = p->to.type; + p->from.index = p->to.index; + break; + } + // fallthrough + case AFMOVF: case AFADDF: case AFSUBF: @@ -250,7 +263,6 @@ progedit(Link *ctxt, Prog *p) case AFDIVRF: case AFCOMF: case AFCOMFP: - case AMOVSS: case AADDSS: case ASUBSS: case AMULSS: @@ -274,6 +286,19 @@ progedit(Link *ctxt, Prog *p) p->from.offset = 0; } break; + + case AMOVSD: + // Convert AMOVSD $(0), Xx to AXORPS Xx, Xx + if(p->from.type == D_FCONST) + if(p->from.u.dval == 0) + if(p->to.type >= D_X0) + if(p->to.type <= D_X15) { + p->as = AXORPS; + p->from.type = p->to.type; + p->from.index = p->to.index; + break; + } + // fallthrough case AFMOVD: case AFADDD: @@ -284,7 +309,6 @@ progedit(Link *ctxt, Prog *p) case AFDIVRD: case AFCOMD: case AFCOMDP: - case AMOVSD: case AADDSD: case ASUBSD: case AMULSD: |