Revert "[DAGCombiner] try repeated fdiv divisor transform before building estimate"

This reverts commit fb9a5307a94e6f1f850e4d89f79103b123f16279 (rL359398)
because it can cause an infinite loop due to opposing combines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359695 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index aeab54d65a8c4970ffdee6cd59dd79424983b834..d1e71237fe841f344a595e450b1eb583f1641a61 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -11993,9 +11993,6 @@ SDValue DAGCombiner::visitFDIV(SDNode *N) {
   if (SDValue NewSel = foldBinOpIntoSelect(N))
     return NewSel;
 
-  if (SDValue V = combineRepeatedFPDivisors(N))
-    return V;
-
   if (Options.UnsafeFPMath || Flags.hasAllowReciprocal()) {
     // fold (fdiv X, c2) -> fmul X, 1/c2 if losing precision is acceptable.
     if (N1CFP) {
@@ -12085,6 +12082,9 @@ SDValue DAGCombiner::visitFDIV(SDNode *N) {
     }
   }
 
+  if (SDValue CombineRepeatedDivisors = combineRepeatedFPDivisors(N))
+    return CombineRepeatedDivisors;
+
   return SDValue();
 }
 

diff --git a/test/CodeGen/X86/fdiv-combine-vec.ll b/test/CodeGen/X86/fdiv-combine-vec.ll
index 825f8a50f96d6ddc907f7db9ae581ae0a2f8b44b..6de3f31892d68974cd45608db87295b7362d8a02 100644 (file)
--- a/test/CodeGen/X86/fdiv-combine-vec.ll
+++ b/test/CodeGen/X86/fdiv-combine-vec.ll
@@ -51,17 +51,25 @@ define <4 x double> @splat_fdiv_v4f64(<4 x double> %x, double %y) {
 define <4 x float> @splat_fdiv_v4f32(<4 x float> %x, float %y) {
 ; SSE-LABEL: splat_fdiv_v4f32:
 ; SSE:       # %bb.0:
-; SSE-NEXT:    movss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; SSE-NEXT:    divss %xmm1, %xmm2
-; SSE-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,0,0,0]
-; SSE-NEXT:    mulps %xmm2, %xmm0
+; SSE-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0,0,0]
+; SSE-NEXT:    rcpps %xmm1, %xmm2
+; SSE-NEXT:    mulps %xmm2, %xmm1
+; SSE-NEXT:    movaps {{.*#+}} xmm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; SSE-NEXT:    subps %xmm1, %xmm3
+; SSE-NEXT:    mulps %xmm2, %xmm3
+; SSE-NEXT:    addps %xmm2, %xmm3
+; SSE-NEXT:    mulps %xmm3, %xmm0
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: splat_fdiv_v4f32:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vmovss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; AVX-NEXT:    vdivss %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vpermilps {{.*#+}} xmm1 = xmm1[0,0,0,0]
+; AVX-NEXT:    vrcpps %xmm1, %xmm2
+; AVX-NEXT:    vmulps %xmm2, %xmm1, %xmm1
+; AVX-NEXT:    vmovaps {{.*#+}} xmm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; AVX-NEXT:    vsubps %xmm1, %xmm3, %xmm1
+; AVX-NEXT:    vmulps %xmm1, %xmm2, %xmm1
+; AVX-NEXT:    vaddps %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vmulps %xmm1, %xmm0, %xmm0
 ; AVX-NEXT:    retq
   %vy = insertelement <4 x float> undef, float %y, i32 0
@@ -82,10 +90,14 @@ define <8 x float> @splat_fdiv_v8f32(<8 x float> %x, float %y) {
 ;
 ; AVX-LABEL: splat_fdiv_v8f32:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vmovss {{.*#+}} xmm2 = mem[0],zero,zero,zero
-; AVX-NEXT:    vdivss %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vpermilps {{.*#+}} xmm1 = xmm1[0,0,0,0]
 ; AVX-NEXT:    vinsertf128 $1, %xmm1, %ymm1, %ymm1
+; AVX-NEXT:    vrcpps %ymm1, %ymm2
+; AVX-NEXT:    vmulps %ymm2, %ymm1, %ymm1
+; AVX-NEXT:    vmovaps {{.*#+}} ymm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; AVX-NEXT:    vsubps %ymm1, %ymm3, %ymm1
+; AVX-NEXT:    vmulps %ymm1, %ymm2, %ymm1
+; AVX-NEXT:    vaddps %ymm1, %ymm2, %ymm1
 ; AVX-NEXT:    vmulps %ymm1, %ymm0, %ymm0
 ; AVX-NEXT:    retq
   %vy = insertelement <8 x float> undef, float %y, i32 0
@@ -97,25 +109,25 @@ define <8 x float> @splat_fdiv_v8f32(<8 x float> %x, float %y) {
 define <4 x float> @splat_fdiv_v4f32_estimate(<4 x float> %x, float %y) #0 {
 ; SSE-LABEL: splat_fdiv_v4f32_estimate:
 ; SSE:       # %bb.0:
-; SSE-NEXT:    rcpss %xmm1, %xmm2
-; SSE-NEXT:    mulss %xmm2, %xmm1
-; SSE-NEXT:    movss {{.*#+}} xmm3 = mem[0],zero,zero,zero
-; SSE-NEXT:    subss %xmm1, %xmm3
-; SSE-NEXT:    mulss %xmm2, %xmm3
-; SSE-NEXT:    addss %xmm2, %xmm3
-; SSE-NEXT:    shufps {{.*#+}} xmm3 = xmm3[0,0,0,0]
+; SSE-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0,0,0]
+; SSE-NEXT:    rcpps %xmm1, %xmm2
+; SSE-NEXT:    mulps %xmm2, %xmm1
+; SSE-NEXT:    movaps {{.*#+}} xmm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; SSE-NEXT:    subps %xmm1, %xmm3
+; SSE-NEXT:    mulps %xmm2, %xmm3
+; SSE-NEXT:    addps %xmm2, %xmm3
 ; SSE-NEXT:    mulps %xmm3, %xmm0
 ; SSE-NEXT:    retq
 ;
 ; AVX-LABEL: splat_fdiv_v4f32_estimate:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vrcpss %xmm1, %xmm1, %xmm2
-; AVX-NEXT:    vmulss %xmm2, %xmm1, %xmm1
-; AVX-NEXT:    vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero
-; AVX-NEXT:    vsubss %xmm1, %xmm3, %xmm1
-; AVX-NEXT:    vmulss %xmm1, %xmm2, %xmm1
-; AVX-NEXT:    vaddss %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vpermilps {{.*#+}} xmm1 = xmm1[0,0,0,0]
+; AVX-NEXT:    vrcpps %xmm1, %xmm2
+; AVX-NEXT:    vmulps %xmm2, %xmm1, %xmm1
+; AVX-NEXT:    vmovaps {{.*#+}} xmm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; AVX-NEXT:    vsubps %xmm1, %xmm3, %xmm1
+; AVX-NEXT:    vmulps %xmm1, %xmm2, %xmm1
+; AVX-NEXT:    vaddps %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vmulps %xmm1, %xmm0, %xmm0
 ; AVX-NEXT:    retq
   %vy = insertelement <4 x float> undef, float %y, i32 0
@@ -140,14 +152,14 @@ define <8 x float> @splat_fdiv_v8f32_estimate(<8 x float> %x, float %y) #0 {
 ;
 ; AVX-LABEL: splat_fdiv_v8f32_estimate:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vrcpss %xmm1, %xmm1, %xmm2
-; AVX-NEXT:    vmulss %xmm2, %xmm1, %xmm1
-; AVX-NEXT:    vmovss {{.*#+}} xmm3 = mem[0],zero,zero,zero
-; AVX-NEXT:    vsubss %xmm1, %xmm3, %xmm1
-; AVX-NEXT:    vmulss %xmm1, %xmm2, %xmm1
-; AVX-NEXT:    vaddss %xmm1, %xmm2, %xmm1
 ; AVX-NEXT:    vpermilps {{.*#+}} xmm1 = xmm1[0,0,0,0]
 ; AVX-NEXT:    vinsertf128 $1, %xmm1, %ymm1, %ymm1
+; AVX-NEXT:    vrcpps %ymm1, %ymm2
+; AVX-NEXT:    vmulps %ymm2, %ymm1, %ymm1
+; AVX-NEXT:    vmovaps {{.*#+}} ymm3 = [1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0,1.0E+0]
+; AVX-NEXT:    vsubps %ymm1, %ymm3, %ymm1
+; AVX-NEXT:    vmulps %ymm1, %ymm2, %ymm1
+; AVX-NEXT:    vaddps %ymm1, %ymm2, %ymm1
 ; AVX-NEXT:    vmulps %ymm1, %ymm0, %ymm0
 ; AVX-NEXT:    retq
   %vy = insertelement <8 x float> undef, float %y, i32 0