https://llvm.org/bugs/show_bug.cgi?id=29078
Bug ID: 29078
Summary: [X86][SSE] Failure to recognise i64 sitofp conversions
can be performed as i32
Product: libraries
Version: trunk
Hardware: PC
OS: All
Status: NEW
Severity: normal
Priority: P
Component: Backend: X86
Assignee: unassignedb...@nondot.org
Reporter: llvm-...@redking.me.uk
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
i64 to f32/f64 sitofp conversions must be performed using gpr source registers,
requiring costly vector/scalar register moves. But if we know that the integers
are within the i32 range then we should be able to use the faster
cvtdq2ps/cvtdq2pd instructions (via suitable truncation/shuffles).
This might be worth performing in DAGCombine, but for now I'm suggesting it
just as a x86 optimization.
define <2 x double> @mask_scvt_2i64_2f64(<2 x i64> %a) {
%and = and <2 x i64> %a, <i64 255, i64 255>
%cvt = sitofp <2 x i64> %and to <2 x double>
ret <2 x double> %cvt
}
define <4 x float> @mask_scvt_4i64_4f32(<4 x i64> %a) {
%and = and <4 x i64> %a, <i64 255, i64 255, i64 255, i64 255>
%cvt = sitofp <4 x i64> %and to <4 x float>
ret <4 x float> %cvt
}
define <2 x double> @clamp_scvt_2i64_2f64(<2 x i64> %a) {
%clo = icmp slt <2 x i64> %a, <i64 -255, i64 -255>
%lo = select <2 x i1> %clo, <2 x i64> <i64 -255, i64 -255>, <2 x i64> %a
%chi = icmp sgt <2 x i64> %lo, <i64 255, i64 255>
%hi = select <2 x i1> %chi, <2 x i64> <i64 255, i64 255>, <2 x i64> %lo
%cvt = sitofp <2 x i64> %hi to <2 x double>
ret <2 x double> %cvt
}
"~/LLVM/build/bin/llc -mcpu=btver2"
_mask_scvt_2i64_2f64:
vpand LCPI0_0(%rip), %xmm0, %xmm0
vpextrq $1, %xmm0, %rax
vmovq %xmm0, %rcx
vcvtsi2sdq %rax, %xmm1, %xmm1
vcvtsi2sdq %rcx, %xmm2, %xmm0
vunpcklpd %xmm1, %xmm0, %xmm0 ## xmm0 = xmm0[0],xmm1[0]
retq
_mask_scvt_4i64_4f32:
vandps LCPI1_0(%rip), %ymm0, %ymm0
vpextrq $1, %xmm0, %rax
vmovq %xmm0, %rdx
vcvtsi2ssq %rax, %xmm1, %xmm1
vcvtsi2ssq %rdx, %xmm2, %xmm2
vextractf128 $1, %ymm0, %xmm0
vmovq %xmm0, %rax
vpextrq $1, %xmm0, %rcx
vinsertps $16, %xmm1, %xmm2, %xmm1 ## xmm1 =
xmm2[0],xmm1[0],xmm2[2,3]
vcvtsi2ssq %rax, %xmm3, %xmm2
vcvtsi2ssq %rcx, %xmm3, %xmm0
vinsertps $32, %xmm2, %xmm1, %xmm1 ## xmm1 =
xmm1[0,1],xmm2[0],xmm1[3]
vinsertps $48, %xmm0, %xmm1, %xmm0 ## xmm0 = xmm1[0,1,2],xmm0[0]
retq
_clamp_scvt_2i64_2f64:
vmovdqa LCPI2_0(%rip), %xmm1 ## xmm1 =
[18446744073709551361,18446744073709551361]
vpcmpgtq %xmm0, %xmm1, %xmm2
vblendvpd %xmm2, %xmm1, %xmm0, %xmm0
vmovdqa LCPI2_1(%rip), %xmm1 ## xmm1 = [255,255]
vpcmpgtq %xmm1, %xmm0, %xmm2
vblendvpd %xmm2, %xmm1, %xmm0, %xmm0
vpextrq $1, %xmm0, %rax
vmovq %xmm0, %rcx
vcvtsi2sdq %rax, %xmm3, %xmm1
vcvtsi2sdq %rcx, %xmm3, %xmm0
vunpcklpd %xmm1, %xmm0, %xmm0 ## xmm0 = xmm0[0],xmm1[0]
retq
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
