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[X86] Add more test cases for fast-isel handling of fneg. 

The fneg double case is falling back to a subsd in 32-bit mode if you write a test that doesn't trigger a fast-isel abort on the return value.

The subsd lowering has different behavior with respect to nans than using an xor. This is inconsisent with what we would do in SelectionDAG
and can lead to differences between -O0 and -O2.

llvm-svn: 360088
This commit is contained in:
Craig Topper 2019-05-06 22:04:26 +00:00
parent 1bc001dec4
commit 77e69d8850
1 changed files with 53 additions and 2 deletions
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55
llvm/test/CodeGen/X86/fast-isel-fneg.ll
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@ -1,6 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -fast-isel -fast-isel-abort=1 -mtriple=x86_64-apple-darwin10 | FileCheck %s
; RUN: llc < %s -fast-isel -mtriple=i686-- -mattr=+sse2 | FileCheck --check-prefix=SSE2 %s
; RUN: llc < %s -fast-isel -fast-isel-abort=3 -mtriple=x86_64-apple-darwin10 | FileCheck %s
; RUN: llc < %s -fast-isel -fast-isel-abort=1 -mtriple=i686-- -mattr=+sse2 | FileCheck --check-prefix=SSE2 %s
define double @doo(double %x) nounwind {
; CHECK-LABEL: doo:
@ -48,3 +48,54 @@ define float @foo(float %x) nounwind {
%y = fsub float -0.0, %x
ret float %y
}
define void @goo(double* %x, double* %y) nounwind {
; CHECK-LABEL: goo:
; CHECK: ## %bb.0:
; CHECK-NEXT: movq {{.*#+}} xmm0 = mem[0],zero
; CHECK-NEXT: movq %xmm0, %rax
; CHECK-NEXT: movabsq $-9223372036854775808, %rcx ## imm = 0x8000000000000000
; CHECK-NEXT: xorq %rax, %rcx
; CHECK-NEXT: movq %rcx, %xmm0
; CHECK-NEXT: movq %xmm0, (%rsi)
; CHECK-NEXT: retq
;
; SSE2-LABEL: goo:
; SSE2: # %bb.0:
; SSE2-NEXT: movl {{[0-9]+}}(%esp), %eax
; SSE2-NEXT: movl {{[0-9]+}}(%esp), %ecx
; SSE2-NEXT: movsd {{.*#+}} xmm0 = mem[0],zero
; SSE2-NEXT: subsd (%ecx), %xmm0
; SSE2-NEXT: movsd %xmm0, (%eax)
; SSE2-NEXT: retl
%a = load double, double* %x
%b = fsub double -0.0, %a
store double %b, double* %y
ret void
}
define void @loo(float* %x, float* %y) nounwind {
; CHECK-LABEL: loo:
; CHECK: ## %bb.0:
; CHECK-NEXT: movd {{.*#+}} xmm0 = mem[0],zero,zero,zero
; CHECK-NEXT: movd %xmm0, %eax
; CHECK-NEXT: xorl $2147483648, %eax ## imm = 0x80000000
; CHECK-NEXT: movd %eax, %xmm0
; CHECK-NEXT: movd %xmm0, (%rsi)
; CHECK-NEXT: retq
;
; SSE2-LABEL: loo:
; SSE2: # %bb.0:
; SSE2-NEXT: movl {{[0-9]+}}(%esp), %eax
; SSE2-NEXT: movl {{[0-9]+}}(%esp), %ecx
; SSE2-NEXT: movd {{.*#+}} xmm0 = mem[0],zero,zero,zero
; SSE2-NEXT: movd %xmm0, %ecx
; SSE2-NEXT: xorl $2147483648, %ecx # imm = 0x80000000
; SSE2-NEXT: movd %ecx, %xmm0
; SSE2-NEXT: movd %xmm0, (%eax)
; SSE2-NEXT: retl
%a = load float, float* %x
%b = fsub float -0.0, %a
store float %b, float* %y
ret void
}