diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp index b933f0324097..eae5a45906f1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp @@ -3075,7 +3075,6 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1, DAG.getConstant(0, dl, N0.getValueType()), Cond); // The shift is not valid if this is a bool (i1). - // TODO: This transform needs evidence to justify its existence. if (N0.getNode()->hasOneUse() && OpVT.getScalarSizeInBits() != 1) { assert(N0.getOpcode() == ISD::SUB && "Unexpected operation!"); auto &DL = DAG.getDataLayout(); diff --git a/llvm/test/CodeGen/X86/setcc-combine.ll b/llvm/test/CodeGen/X86/setcc-combine.ll index c13d2f114cf9..ed3dfcdd7b1d 100644 --- a/llvm/test/CodeGen/X86/setcc-combine.ll +++ b/llvm/test/CodeGen/X86/setcc-combine.ll @@ -297,3 +297,41 @@ define i64 @sub_to_shift_to_add(i32 %x, i32 %y, i64 %s1, i64 %s2) { ret i64 %r } +define <4 x float> @sub_to_shift_to_add_vec(<4 x i32> %x, <4 x i32> %y, <4 x float> %s1, <4 x float> %s2) { +; SSE2-LABEL: sub_to_shift_to_add_vec: +; SSE2: # %bb.0: +; SSE2-NEXT: paddd %xmm1, %xmm1 +; SSE2-NEXT: pcmpeqd %xmm0, %xmm1 +; SSE2-NEXT: pand %xmm1, %xmm2 +; SSE2-NEXT: pandn %xmm3, %xmm1 +; SSE2-NEXT: por %xmm2, %xmm1 +; SSE2-NEXT: movdqa %xmm1, %xmm0 +; SSE2-NEXT: retq +; +; SSE41-LABEL: sub_to_shift_to_add_vec: +; SSE41: # %bb.0: +; SSE41-NEXT: paddd %xmm1, %xmm1 +; SSE41-NEXT: pcmpeqd %xmm1, %xmm0 +; SSE41-NEXT: blendvps %xmm0, %xmm2, %xmm3 +; SSE41-NEXT: movaps %xmm3, %xmm0 +; SSE41-NEXT: retq + %sub = sub <4 x i32> %x, %y + %cmp = icmp eq <4 x i32> %sub, %y + %r = select <4 x i1> %cmp, <4 x float> %s1, <4 x float> %s2 + ret <4 x float> %r +} + +define i64 @sub_constant_to_shift_to_add(i32 %x, i64 %s1, i64 %s2) { +; CHECK-LABEL: sub_constant_to_shift_to_add: +; CHECK: # %bb.0: +; CHECK-NEXT: movq %rsi, %rax +; CHECK-NEXT: addl %edi, %edi +; CHECK-NEXT: cmpl $42, %edi +; CHECK-NEXT: cmovneq %rdx, %rax +; CHECK-NEXT: retq + %sub = sub i32 42, %x + %cmp = icmp eq i32 %sub, %x + %r = select i1 %cmp, i64 %s1, i64 %s2 + ret i64 %r +} +