Many SSE cvt instructions take 64bit memory source
instead of 128bit. In
(define_insn "sse2_cvtps2pd"
[(set (match_operand:V2DF 0 "register_operand" "=x")
(float_extend:V2DF
(vec_select:V2SF
(match_operand:V4SF 1 "nonimmediate_operand" "xm")
(parallel [(const_int 0) (const_int 1)]))))]
"TARGET_SSE2"
"%vcvtps2pd\t{%1, %0|%0, %1}"
[(set_attr "type" "ssecvt")
(set_attr "prefix" "maybe_vex")
(set_attr "mode" "V2DF")
(set_attr "prefix_data16" "0")
(set_attr "amdfam10_decode" "direct")])
memory operand is V2SF, not V4SF. As the result, we get
[...@gnu-6 tmp]$ cat x.c
float v2sf[8] __attribute ((aligned(16)));
double v4df[8] __attribute ((aligned(16)));
void
foo ()
{
int i;
for (i = 0; i < 8; i++)
v4df[i] = v2sf[i];
}
[...@gnu-6 tmp]$ /usr/gcc-4.5/bin/gcc -S -O3 x.c
[...@gnu-6 tmp]$ cat x.s
.file "x.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
movaps v2sf(%rip), %xmm1
cvtps2pd %xmm1, %xmm0
movapd %xmm0, v4df(%rip)
xorps %xmm0, %xmm0
movhlps %xmm1, %xmm0
movaps v2sf+16(%rip), %xmm1
cvtps2pd %xmm0, %xmm0
movapd %xmm0, v4df+16(%rip)
cvtps2pd %xmm1, %xmm0
movapd %xmm0, v4df+32(%rip)
xorps %xmm0, %xmm0
movhlps %xmm1, %xmm0
cvtps2pd %xmm0, %xmm0
movapd %xmm0, v4df+48(%rip)
ret
instead of
[...@gnu-6 tmp]$ /opt/intel/Compiler/11.1/059/bin/intel64/icc -S -O2 x.c
[...@gnu-6 tmp]$ cat x.s
# -- Machine type EFI2
# mark_description "Intel(R) C++ Compiler for applications running on Intel(R)
64, Version 11.1 Build 20091012 %s";
# mark_description "-S -O2";
.file "x.c"
.text
..TXTST0:
# -- Begin foo
# mark_begin;
.align 16,0x90
.globl foo
foo:
..B1.1: # Preds ..B1.0
..___tag_value_foo.1: #5.1
cvtps2pd v2sf(%rip), %xmm0 #8.15
cvtps2pd 8+v2sf(%rip), %xmm1 #8.15
cvtps2pd 16+v2sf(%rip), %xmm2 #8.15
cvtps2pd 24+v2sf(%rip), %xmm3 #8.15
movaps %xmm0, v4df(%rip) #8.5
movaps %xmm1, 16+v4df(%rip) #8.5
movaps %xmm2, 32+v4df(%rip) #8.5
movaps %xmm3, 48+v4df(%rip) #8.5
ret #9.1
--
Summary: Incorrect sse2_cvtX2Y pattern
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl dot tools at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43618
