[llvm] r220777 - [x86] Simplify vector selection if condition value type matches vselect value type and true value is all ones or false value is all zeros.

[Robert Khasanov]

Author: rkhasanov
Date: Tue Oct 28 10:59:40 2014
New Revision: 220777

URL: http://llvm.org/viewvc/llvm-project?rev=220777&view=rev
Log:
[x86] Simplify vector selection if condition value type matches vselect value type and true value is all ones or false value is all zeros.
This transformation worked if selector is produced by SETCC, however SETCC is needed only if we consider to swap operands. So I replaced SETCC check for this case.
Added tests for vselect of <X x i1> values.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/avx512-select.ll
    llvm/trunk/test/CodeGen/X86/vselect-avx.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=220777&r1=220776&r2=220777&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Tue Oct 28 10:59:40 2014
@@ -22479,22 +22479,22 @@ static SDValue PerformSELECTCombine(SDNo
       return DAG.getNode(Opc, DL, VT, LHS, RHS);
   }
 
-  // Simplify vector selection if the selector will be produced by CMPP*/PCMP*.
-  if (N->getOpcode() == ISD::VSELECT && Cond.getOpcode() == ISD::SETCC &&
-      // Check if SETCC has already been promoted
-      TLI.getSetCCResultType(*DAG.getContext(), VT) == CondVT &&
-      // Check that condition value type matches vselect operand type
-      CondVT == VT) { 
-
+  // Simplify vector selection if condition value type matches vselect
+  // operand type
+  if (N->getOpcode() == ISD::VSELECT && CondVT == VT) {
     assert(Cond.getValueType().isVector() &&
            "vector select expects a vector selector!");
 
     bool TValIsAllOnes = ISD::isBuildVectorAllOnes(LHS.getNode());
     bool FValIsAllZeros = ISD::isBuildVectorAllZeros(RHS.getNode());
 
-    if (!TValIsAllOnes && !FValIsAllZeros) {
-      // Try invert the condition if true value is not all 1s and false value
-      // is not all 0s.
+    // Try invert the condition if true value is not all 1s and false value
+    // is not all 0s.
+    if (!TValIsAllOnes && !FValIsAllZeros &&
+        // Check if the selector will be produced by CMPP*/PCMP*
+        Cond.getOpcode() == ISD::SETCC &&
+        // Check if SETCC has already been promoted
+        TLI.getSetCCResultType(*DAG.getContext(), VT) == CondVT) {
       bool TValIsAllZeros = ISD::isBuildVectorAllZeros(LHS.getNode());
       bool FValIsAllOnes = ISD::isBuildVectorAllOnes(RHS.getNode());
 

Modified: llvm/trunk/test/CodeGen/X86/avx512-select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx512-select.ll?rev=220777&r1=220776&r2=220777&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/avx512-select.ll (original)
+++ llvm/trunk/test/CodeGen/X86/avx512-select.ll Tue Oct 28 10:59:40 2014
@@ -48,3 +48,47 @@ define <16 x double> @select04(<16 x dou
   %sel = select <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false, i1 false>, <16 x double> %a, <16 x double> %b
   ret <16 x double> %sel
 }
+
+; CHECK-LABEL: select05
+; CHECK: kmovw   %esi, %k0
+; CHECK-NEXT: kmovw   %edi, %k1
+; CHECK-NEXT: korw    %k1, %k0, %k0
+; CHECK-NEXT: kmovw   %k0, %eax
+define i8 @select05(i8 %a.0, i8 %m) {
+  %mask = bitcast i8 %m to <8 x i1>
+  %a = bitcast i8 %a.0 to <8 x i1>
+  %r = select <8 x i1> %mask, <8 x i1> <i1 -1, i1 -1, i1 -1, i1 -1, i1 -1, i1 -1, i1 -1, i1 -1>, <8 x i1> %a
+  %res = bitcast <8 x i1> %r to i8
+  ret i8 %res;
+}
+
+; CHECK-LABEL: select06
+; CHECK: kmovw   %esi, %k0
+; CHECK-NEXT: kmovw   %edi, %k1
+; CHECK-NEXT: kandw    %k1, %k0, %k0
+; CHECK-NEXT: kmovw   %k0, %eax
+define i8 @select06(i8 %a.0, i8 %m) {
+  %mask = bitcast i8 %m to <8 x i1>
+  %a = bitcast i8 %a.0 to <8 x i1>
+  %r = select <8 x i1> %mask, <8 x i1> %a, <8 x i1> zeroinitializer
+  %res = bitcast <8 x i1> %r to i8
+  ret i8 %res;
+}
+
+; CHECK-LABEL: select07
+; CHECK-DAG:  kmovw   %edx, %k0
+; CHECK-DAG:  kmovw   %edi, %k1
+; CHECK-DAG:  kmovw   %esi, %k2
+; CHECK: kandw %k0, %k1, %k1
+; CHECK-NEXT: knotw    %k0, %k0
+; CHECK-NEXT: kandw    %k0, %k2, %k0
+; CHECK-NEXT: korw %k0, %k1, %k0
+; CHECK-NEXT: kmovw   %k0, %eax
+define i8 @select07(i8 %a.0, i8 %b.0, i8 %m) {
+  %mask = bitcast i8 %m to <8 x i1>
+  %a = bitcast i8 %a.0 to <8 x i1>
+  %b = bitcast i8 %b.0 to <8 x i1>
+  %r = select <8 x i1> %mask, <8 x i1> %a, <8 x i1> %b
+  %res = bitcast <8 x i1> %r to i8
+  ret i8 %res;
+}

Modified: llvm/trunk/test/CodeGen/X86/vselect-avx.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vselect-avx.ll?rev=220777&r1=220776&r2=220777&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vselect-avx.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vselect-avx.ll Tue Oct 28 10:59:40 2014
@@ -14,8 +14,8 @@ target triple = "x86_64-apple-macosx"
 ; <rdar://problem/18675020>
 
 ; CHECK-LABEL: test:
-; CHECK: vmovdqa {{.*#+}} xmm1 = [65533,124,125,14807]
-; CHECK: vmovdqa {{.*#+}} xmm1 = [65535,0,0,65535]
+; CHECK: vmovdqa {{.*#+}} xmm0 = [65535,0,0,65535]
+; CHECK: vmovdqa {{.*#+}} xmm2 = [65533,124,125,14807]
 ; CHECK: ret
 define void @test(<4 x i16>* %a, <4 x i16>* %b) {
 body: