[TargetLowering] SimplifyDemandedBits - add ISD::INSERT_SUBVECTOR support

llvm-svn: 358019

2 files changed, 50 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index ab934d18aee..4d5dae7d960 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -595,6 +595,45 @@ bool TargetLowering::SimplifyDemandedBits(
 
     return false;
   }
+  case ISD::INSERT_SUBVECTOR: {
+    SDValue Base = Op.getOperand(0);
+    SDValue Sub = Op.getOperand(1);
+    EVT SubVT = Sub.getValueType();
+    unsigned NumSubElts = SubVT.getVectorNumElements();
+
+    // If index isn't constant, assume we need the original demanded base
+    // elements and ALL the inserted subvector elements.
+    APInt BaseElts = DemandedElts;
+    APInt SubElts = APInt::getAllOnesValue(NumSubElts);
+    if (isa<ConstantSDNode>(Op.getOperand(2))) {
+      const APInt &Idx = Op.getConstantOperandAPInt(2);
+      if (Idx.ule(NumElts - NumSubElts)) {
+        unsigned SubIdx = Idx.getZExtValue();
+        SubElts = DemandedElts.extractBits(NumSubElts, SubIdx);
+        BaseElts.insertBits(APInt::getNullValue(NumSubElts), SubIdx);
+      }
+    }
+
+    KnownBits KnownSub, KnownBase;
+    if (SimplifyDemandedBits(Sub, DemandedBits, SubElts, KnownSub, TLO,
+                             Depth + 1))
+      return true;
+    if (SimplifyDemandedBits(Base, DemandedBits, BaseElts, KnownBase, TLO,
+                             Depth + 1))
+      return true;
+
+    Known.Zero.setAllBits();
+    Known.One.setAllBits();
+    if (!!SubElts) {
+        Known.One &= KnownSub.One;
+        Known.Zero &= KnownSub.Zero;
+    }
+    if (!!BaseElts) {
+        Known.One &= KnownBase.One;
+        Known.Zero &= KnownBase.Zero;
+    }
+    break;
+  }
   case ISD::CONCAT_VECTORS: {
     Known.Zero.setAllBits();
     Known.One.setAllBits();
diff --git a/llvm/test/CodeGen/X86/avx512-mask-op.ll b/llvm/test/CodeGen/X86/avx512-mask-op.ll
index 7a7b79c4f52..96bbadba695 100644
--- a/llvm/test/CodeGen/X86/avx512-mask-op.ll
+++ b/llvm/test/CodeGen/X86/avx512-mask-op.ll
@@ -1069,10 +1069,9 @@ define <64 x i8> @test16(i64 %x) {
 ; KNL-NEXT:    kmovw %ecx, %k1
 ; KNL-NEXT:    kmovw %eax, %k2
 ; KNL-NEXT:    kmovw %edi, %k3
-; KNL-NEXT:    movb $1, %al
-; KNL-NEXT:    kmovw %eax, %k4
-; KNL-NEXT:    kshiftrw $5, %k0, %k5
-; KNL-NEXT:    kxorw %k4, %k5, %k4
+; KNL-NEXT:    kshiftrw $5, %k0, %k4
+; KNL-NEXT:    kxnorw %k0, %k0, %k5
+; KNL-NEXT:    kxorw %k5, %k4, %k4
 ; KNL-NEXT:    kshiftlw $15, %k4, %k4
 ; KNL-NEXT:    kshiftrw $10, %k4, %k4
 ; KNL-NEXT:    kxorw %k4, %k0, %k4
@@ -1091,8 +1090,7 @@ define <64 x i8> @test16(i64 %x) {
 ; SKX-LABEL: test16:
 ; SKX:       ## %bb.0:
 ; SKX-NEXT:    kmovq %rdi, %k0
-; SKX-NEXT:    movb $1, %al
-; SKX-NEXT:    kmovd %eax, %k1
+; SKX-NEXT:    kxnorw %k0, %k0, %k1
 ; SKX-NEXT:    kshiftrq $5, %k0, %k2
 ; SKX-NEXT:    kxorq %k1, %k2, %k1
 ; SKX-NEXT:    kshiftlq $63, %k1, %k1
@@ -1104,8 +1102,7 @@ define <64 x i8> @test16(i64 %x) {
 ; AVX512BW-LABEL: test16:
 ; AVX512BW:       ## %bb.0:
 ; AVX512BW-NEXT:    kmovq %rdi, %k0
-; AVX512BW-NEXT:    movb $1, %al
-; AVX512BW-NEXT:    kmovd %eax, %k1
+; AVX512BW-NEXT:    kxnorw %k0, %k0, %k1
 ; AVX512BW-NEXT:    kshiftrq $5, %k0, %k2
 ; AVX512BW-NEXT:    kxorq %k1, %k2, %k1
 ; AVX512BW-NEXT:    kshiftlq $63, %k1, %k1
@@ -1125,10 +1122,9 @@ define <64 x i8> @test16(i64 %x) {
 ; AVX512DQ-NEXT:    kmovw %ecx, %k1
 ; AVX512DQ-NEXT:    kmovw %eax, %k2
 ; AVX512DQ-NEXT:    kmovw %edi, %k3
-; AVX512DQ-NEXT:    movb $1, %al
-; AVX512DQ-NEXT:    kmovw %eax, %k4
-; AVX512DQ-NEXT:    kshiftrw $5, %k0, %k5
-; AVX512DQ-NEXT:    kxorw %k4, %k5, %k4
+; AVX512DQ-NEXT:    kshiftrw $5, %k0, %k4
+; AVX512DQ-NEXT:    kxnorw %k0, %k0, %k5
+; AVX512DQ-NEXT:    kxorw %k5, %k4, %k4
 ; AVX512DQ-NEXT:    kshiftlw $15, %k4, %k4
 ; AVX512DQ-NEXT:    kshiftrw $10, %k4, %k4
 ; AVX512DQ-NEXT:    kxorw %k4, %k0, %k0
@@ -1147,10 +1143,9 @@ define <64 x i8> @test16(i64 %x) {
 ; X86-LABEL: test16:
 ; X86:       ## %bb.0:
 ; X86-NEXT:    kmovq {{[0-9]+}}(%esp), %k0
-; X86-NEXT:    movb $1, %al
-; X86-NEXT:    kmovd %eax, %k1
-; X86-NEXT:    kshiftrq $5, %k0, %k2
-; X86-NEXT:    kxorq %k1, %k2, %k1
+; X86-NEXT:    kshiftrq $5, %k0, %k1
+; X86-NEXT:    kxnorw %k0, %k0, %k2
+; X86-NEXT:    kxorq %k2, %k1, %k1
 ; X86-NEXT:    kshiftlq $63, %k1, %k1
 ; X86-NEXT:    kshiftrq $58, %k1, %k1
 ; X86-NEXT:    kxorq %k1, %k0, %k0