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c6058e2462
Since the result of a SETCC for X86 is 0 or -1 in each lane, we can
move unary operations, in this case [su]int_to_fp through the mask
operation and constant fold the operation away. Generally speaking:
UNARYOP(AND(VECTOR_CMP(x,y), constant))
--> AND(VECTOR_CMP(x,y), constant2)
where constant2 is UNARYOP(constant).
This implements the transform where UNARYOP is [su]int_to_fp.
For example, consider the simple function:
define <4 x float> @foo(<4 x float> %val, <4 x float> %test) nounwind {
%cmp = fcmp oeq <4 x float> %val, %test
%ext = zext <4 x i1> %cmp to <4 x i32>
%result = sitofp <4 x i32> %ext to <4 x float>
ret <4 x float> %result
}
Before this change, the SSE code is generated as:
LCPI0_0:
.long 1 ## 0x1
.long 1 ## 0x1
.long 1 ## 0x1
.long 1 ## 0x1
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 4, 0x90
_foo: ## @foo
cmpeqps %xmm1, %xmm0
andps LCPI0_0(%rip), %xmm0
cvtdq2ps %xmm0, %xmm0
retq
After, the code is improved to:
LCPI0_0:
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.long 1065353216 ## float 1.000000e+00
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 4, 0x90
_foo: ## @foo
cmpeqps %xmm1, %xmm0
andps LCPI0_0(%rip), %xmm0
retq
The cvtdq2ps has been constant folded away and the floating point 1.0f
vector lanes are materialized directly via the ModRM operand of andps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213342 91177308-0d34-0410-b5e6-96231b3b80d8
19 lines
691 B
LLVM
19 lines
691 B
LLVM
; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
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define <4 x float> @foo(<4 x float> %val, <4 x float> %test) nounwind {
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; CHECK-LABEL: LCPI0_0
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; CHECK-NEXT: .long 1065353216 ## float 1.000000e+00
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; CHECK-NEXT: .long 1065353216 ## float 1.000000e+00
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; CHECK-NEXT: .long 1065353216 ## float 1.000000e+00
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; CHECK-NEXT: .long 1065353216 ## float 1.000000e+00
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; CHECK-LABEL: foo:
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; CHECK: cmpeqps %xmm1, %xmm0
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; CHECK-NEXT: andps LCPI0_0(%rip), %xmm0
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; CHECK-NEXT: retq
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%cmp = fcmp oeq <4 x float> %val, %test
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%ext = zext <4 x i1> %cmp to <4 x i32>
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%result = sitofp <4 x i32> %ext to <4 x float>
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ret <4 x float> %result
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}
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