dagcombine-unsafe-math.ll
1.86 KB
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; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7-avx | FileCheck %s
; rdar://13126763
; Expression "x + x*x" was mistakenly transformed into "x * 3.0f".
define float @test1(float %x) {
; CHECK-LABEL: test1:
; CHECK: ## %bb.0:
; CHECK-NEXT: vmulss %xmm0, %xmm0, %xmm1
; CHECK-NEXT: vaddss %xmm0, %xmm1, %xmm0
; CHECK-NEXT: retq
%t1 = fmul fast float %x, %x
%t2 = fadd fast float %t1, %x
ret float %t2
}
; (x + x) + x => x * 3.0
define float @test2(float %x) {
; CHECK-LABEL: test2:
; CHECK: ## %bb.0:
; CHECK-NEXT: vmulss {{.*}}(%rip), %xmm0, %xmm0
; CHECK-NEXT: retq
%t1 = fadd fast float %x, %x
%t2 = fadd fast float %t1, %x
ret float %t2
}
; x + (x + x) => x * 3.0
define float @test3(float %x) {
; CHECK-LABEL: test3:
; CHECK: ## %bb.0:
; CHECK-NEXT: vmulss {{.*}}(%rip), %xmm0, %xmm0
; CHECK-NEXT: retq
%t1 = fadd fast float %x, %x
%t2 = fadd fast float %x, %t1
ret float %t2
}
; (y + x) + x != x * 3.0
define float @test4(float %x, float %y) {
; CHECK-LABEL: test4:
; CHECK: ## %bb.0:
; CHECK-NEXT: vaddss %xmm1, %xmm0, %xmm1
; CHECK-NEXT: vaddss %xmm0, %xmm1, %xmm0
; CHECK-NEXT: retq
%t1 = fadd fast float %x, %y
%t2 = fadd fast float %t1, %x
ret float %t2
}
; rdar://13445387
; "x + x + x => 3.0 * x" should be disabled after legalization because
; Instruction-Selection doesn't know how to handle "3.0"
;
define float @test5(<4 x float> %x) {
; CHECK-LABEL: test5:
; CHECK: ## %bb.0:
; CHECK-NEXT: vmulss {{.*}}(%rip), %xmm0, %xmm0
; CHECK-NEXT: retq
%splat = shufflevector <4 x float> %x, <4 x float> undef, <4 x i32> zeroinitializer
%v1 = extractelement <4 x float> %splat, i32 1
%v0 = extractelement <4 x float> %splat, i32 0
%add1 = fadd reassoc nsz float %v0, %v1
%v2 = extractelement <4 x float> %splat, i32 2
%add2 = fadd reassoc nsz float %v2, %add1
ret float %add2
}