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| author | Sanjay Patel <spatel@rotateright.com> | 2019-09-25 15:08:33 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2019-09-25 15:08:33 +0000 |
| commit | 831a7e7068f78be7108672ca6dc66721000fdf61 (patch) | |
| tree | 1abede5e93e2811c2b11141b3ba5859a204246eb | |
| parent | 5c3bc3c930d3993a2c5f581112c18a9eb0ba6838 (diff) | |
| download | bcm5719-llvm-831a7e7068f78be7108672ca6dc66721000fdf61.tar.gz bcm5719-llvm-831a7e7068f78be7108672ca6dc66721000fdf61.zip | |
[DAGCombiner] add one-use restriction to vector transform with cheap extract
We might be able to do better on the example in the test,
but in general, we should not scalarize a splatted vector
binop if there are other uses of the binop. Otherwise, we
can end up with code as we had - a scalar op that is
redundant with a vector op.
llvm-svn: 372886
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/scalarize-fp.ll | 17 |
2 files changed, 8 insertions, 11 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 2b47407393d..80afbbee1b1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -18990,7 +18990,7 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { // build_vector. if (SVN->isSplat() && SVN->getSplatIndex() < (int)NumElts) { int SplatIndex = SVN->getSplatIndex(); - if (TLI.isExtractVecEltCheap(VT, SplatIndex) && + if (N0.hasOneUse() && TLI.isExtractVecEltCheap(VT, SplatIndex) && TLI.isBinOp(N0.getOpcode()) && N0.getNode()->getNumValues() == 1) { // splat (vector_bo L, R), Index --> // splat (scalar_bo (extelt L, Index), (extelt R, Index)) diff --git a/llvm/test/CodeGen/X86/scalarize-fp.ll b/llvm/test/CodeGen/X86/scalarize-fp.ll index 5c72d4ba3c0..5b98272fdce 100644 --- a/llvm/test/CodeGen/X86/scalarize-fp.ll +++ b/llvm/test/CodeGen/X86/scalarize-fp.ll @@ -777,21 +777,18 @@ define <8 x float> @splat0_fdiv_const_op0_v8f32(<8 x float> %vx) { define <4 x float> @multi_use_binop(<4 x float> %x, <4 x float> %y) { ; SSE-LABEL: multi_use_binop: ; SSE: # %bb.0: -; SSE-NEXT: movaps %xmm0, %xmm2 -; SSE-NEXT: mulps %xmm1, %xmm2 -; SSE-NEXT: mulss %xmm1, %xmm0 -; SSE-NEXT: shufps {{.*#+}} xmm0 = xmm0[0,0,0,0] -; SSE-NEXT: movlhps {{.*#+}} xmm1 = xmm1[0],xmm2[0] +; SSE-NEXT: mulps %xmm1, %xmm0 +; SSE-NEXT: movlhps {{.*#+}} xmm1 = xmm1[0],xmm0[0] +; SSE-NEXT: shufps {{.*#+}} xmm0 = xmm0[0,1,2,0] ; SSE-NEXT: addps %xmm1, %xmm0 ; SSE-NEXT: retq ; ; AVX-LABEL: multi_use_binop: ; AVX: # %bb.0: -; AVX-NEXT: vmulps %xmm1, %xmm0, %xmm2 -; AVX-NEXT: vmulss %xmm1, %xmm0, %xmm0 -; AVX-NEXT: vpermilps {{.*#+}} xmm0 = xmm0[0,0,0,0] -; AVX-NEXT: vmovddup {{.*#+}} xmm1 = xmm2[0,0] -; AVX-NEXT: vaddps %xmm1, %xmm0, %xmm0 +; AVX-NEXT: vmulps %xmm1, %xmm0, %xmm0 +; AVX-NEXT: vpermilps {{.*#+}} xmm1 = xmm0[0,1,2,0] +; AVX-NEXT: vmovddup {{.*#+}} xmm0 = xmm0[0,0] +; AVX-NEXT: vaddps %xmm0, %xmm1, %xmm0 ; AVX-NEXT: retq %mul = fmul <4 x float> %x, %y %mul0 = shufflevector <4 x float> %mul, <4 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 undef, i32 0> |
