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

topperc · topperc · commit c2f2a95a8abc · 2019-05-06T22:04:26.000Z
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360088 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/fast-isel-fneg.ll b/test/CodeGen/X86/fast-isel-fneg.ll
@@ -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
+}
