[wasm-simd][ia32] Optimize pmin/pmax for AVX

We don't need DefineSameAsFirst for AVX, this can save some moves.

Bug: v8:11190
Change-Id: I301896527cbeab62636b4af744ab0d3b42094ae2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2727152Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73177}

src/compiler/backend/ia32/code-generator-ia32.cc

@@ -1997,15 +1997,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       break;
     }
     case kIA32F64x2Pmin: {
-      XMMRegister dst = i.OutputSimd128Register();
-      DCHECK_EQ(dst, i.InputSimd128Register(0));
-      __ Minpd(dst, dst, i.InputSimd128Register(1));
+      __ Minpd(i.OutputSimd128Register(), i.InputSimd128Register(0),
+               i.InputSimd128Register(1));
       break;
     }
     case kIA32F64x2Pmax: {
-      XMMRegister dst = i.OutputSimd128Register();
-      DCHECK_EQ(dst, i.InputSimd128Register(0));
-      __ Maxpd(dst, dst, i.InputSimd128Register(1));
+      __ Maxpd(i.OutputSimd128Register(), i.InputSimd128Register(0),
+               i.InputSimd128Register(1));
       break;
     }
     case kIA32F64x2Round: {
@@ -2524,15 +2522,13 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       break;
     }
     case kIA32F32x4Pmin: {
-      XMMRegister dst = i.OutputSimd128Register();
-      DCHECK_EQ(dst, i.InputSimd128Register(0));
-      __ Minps(dst, dst, i.InputSimd128Register(1));
+      __ Minps(i.OutputSimd128Register(), i.InputSimd128Register(0),
+               i.InputSimd128Register(1));
       break;
     }
     case kIA32F32x4Pmax: {
-      XMMRegister dst = i.OutputSimd128Register();
-      DCHECK_EQ(dst, i.InputSimd128Register(0));
-      __ Maxps(dst, dst, i.InputSimd128Register(1));
+      __ Maxps(i.OutputSimd128Register(), i.InputSimd128Register(0),
+               i.InputSimd128Register(1));
       break;
     }
     case kIA32F32x4Round: {

src/compiler/backend/ia32/instruction-selector-ia32.cc

@@ -3039,8 +3039,10 @@ void VisitPminOrPmax(InstructionSelector* selector, Node* node,
   // Due to the way minps/minpd work, we want the dst to be same as the second
   // input: b = pmin(a, b) directly maps to minps b a.
   IA32OperandGenerator g(selector);
-  selector->Emit(opcode, g.DefineSameAsFirst(node),
-                 g.UseRegister(node->InputAt(1)),
+  InstructionOperand dst = selector->IsSupported(AVX)
+                               ? g.DefineAsRegister(node)
+                               : g.DefineSameAsFirst(node);
+  selector->Emit(opcode, dst, g.UseRegister(node->InputAt(1)),
                  g.UseRegister(node->InputAt(0)));
 }
 }  // namespace