PPC [wasm-simd]: Prototype sign select

Code fo Instruction Selection is added to the comments
and should be added when opcode is moved out of being a prototype.

Bug: v8:10983
Change-Id: I55948208e0ba0e903b267e0ca3e5815cb673d264
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2642155Reviewed-by: Junliang Yan <junyan@redhat.com>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72241}

src/compiler/backend/ppc/code-generator-ppc.cc

@@ -3742,6 +3742,31 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
                     i.InputSimd128Register(1), kScratchSimd128Reg);
       break;
     }
+#define SIGN_SELECT(compare_gt)                                        \
+  Simd128Register src0 = i.InputSimd128Register(0);                    \
+  Simd128Register src1 = i.InputSimd128Register(1);                    \
+  Simd128Register src2 = i.InputSimd128Register(2);                    \
+  Simd128Register dst = i.OutputSimd128Register();                     \
+  __ vxor(kScratchSimd128Reg, kScratchSimd128Reg, kScratchSimd128Reg); \
+  __ compare_gt(kScratchSimd128Reg, kScratchSimd128Reg, src2);         \
+  __ vsel(dst, src1, src0, kScratchSimd128Reg);
+    case kPPC_I8x16SignSelect: {
+      SIGN_SELECT(vcmpgtsb)
+      break;
+    }
+    case kPPC_I16x8SignSelect: {
+      SIGN_SELECT(vcmpgtsh)
+      break;
+    }
+    case kPPC_I32x4SignSelect: {
+      SIGN_SELECT(vcmpgtsw)
+      break;
+    }
+    case kPPC_I64x2SignSelect: {
+      SIGN_SELECT(vcmpgtsd)
+      break;
+    }
+#undef SIGN_SELECT
     case kPPC_StoreCompressTagged: {
       ASSEMBLE_STORE_INTEGER(StoreTaggedField, StoreTaggedFieldX);
       break;

src/compiler/backend/ppc/instruction-codes-ppc.h

@@ -268,6 +268,7 @@ namespace compiler {
   V(PPC_I64x2SConvertI32x4High)      \
   V(PPC_I64x2UConvertI32x4Low)       \
   V(PPC_I64x2UConvertI32x4High)      \
+  V(PPC_I64x2SignSelect)             \
   V(PPC_I32x4Splat)                  \
   V(PPC_I32x4ExtractLane)            \
   V(PPC_I32x4ReplaceLane)            \
@@ -300,6 +301,7 @@ namespace compiler {
   V(PPC_I32x4DotI16x8S)              \
   V(PPC_I32x4ExtAddPairwiseI16x8S)   \
   V(PPC_I32x4ExtAddPairwiseI16x8U)   \
+  V(PPC_I32x4SignSelect)             \
   V(PPC_F32x4Qfma)                   \
   V(PPC_F32x4Qfms)                   \
   V(PPC_I16x8Splat)                  \
@@ -340,6 +342,7 @@ namespace compiler {
   V(PPC_I16x8ExtAddPairwiseI8x16S)   \
   V(PPC_I16x8ExtAddPairwiseI8x16U)   \
   V(PPC_I16x8Q15MulRSatS)            \
+  V(PPC_I16x8SignSelect)             \
   V(PPC_I8x16Splat)                  \
   V(PPC_I8x16ExtractLaneU)           \
   V(PPC_I8x16ExtractLaneS)           \
@@ -372,6 +375,7 @@ namespace compiler {
   V(PPC_I8x16Shuffle)                \
   V(PPC_I8x16Swizzle)                \
   V(PPC_I8x16BitMask)                \
+  V(PPC_I8x16SignSelect)             \
   V(PPC_V64x2AnyTrue)                \
   V(PPC_V32x4AnyTrue)                \
   V(PPC_V16x8AnyTrue)                \

src/compiler/backend/ppc/instruction-scheduler-ppc.cc

@@ -193,6 +193,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_I64x2SConvertI32x4High:
     case kPPC_I64x2UConvertI32x4Low:
     case kPPC_I64x2UConvertI32x4High:
+    case kPPC_I64x2SignSelect:
     case kPPC_I32x4Splat:
     case kPPC_I32x4ExtractLane:
     case kPPC_I32x4ReplaceLane:
@@ -225,6 +226,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_I32x4DotI16x8S:
     case kPPC_I32x4ExtAddPairwiseI16x8S:
     case kPPC_I32x4ExtAddPairwiseI16x8U:
+    case kPPC_I32x4SignSelect:
     case kPPC_I16x8Splat:
     case kPPC_I16x8ExtractLaneU:
     case kPPC_I16x8ExtractLaneS:
@@ -263,6 +265,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_I16x8ExtAddPairwiseI8x16S:
     case kPPC_I16x8ExtAddPairwiseI8x16U:
     case kPPC_I16x8Q15MulRSatS:
+    case kPPC_I16x8SignSelect:
     case kPPC_I8x16Splat:
     case kPPC_I8x16ExtractLaneU:
     case kPPC_I8x16ExtractLaneS:
@@ -295,6 +298,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kPPC_I8x16Shuffle:
     case kPPC_I8x16Swizzle:
     case kPPC_I8x16BitMask:
+    case kPPC_I8x16SignSelect:
     case kPPC_V64x2AnyTrue:
     case kPPC_V32x4AnyTrue:
     case kPPC_V16x8AnyTrue: