[msan] Handle Intrinsic::vector_reduce_f{add,mul}

This adds handleVectorReduceWithStarterIntrinsic() (similar to handleVectorReduceIntrinsic but for intrinsics with an additional starting parameter) and uses it to handle Intrinsic::vector_reduce_f{add,mul}.

Updates the tests from llvm#125597

Author: thurstond

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -3500,6 +3500,18 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     setOrigin(&I, getOrigin(&I, 0));
   }
 
+  // Similar to handleVectorReduceIntrinsic but with an initial starting value.
+  // e.g., call float @llvm.vector.reduce.fadd.f32.v2f32(float %a0, <2 x float> %a1)
+  //       shadow = shadow[a0] | shadow[a1.0] | shadow[a1.1]
+  void handleVectorReduceWithStarterIntrinsic(IntrinsicInst &I) {
+    IRBuilder<> IRB(&I);
+    Value *Shadow0 = getShadow(&I, 0);
+    Value *Shadow1 = IRB.CreateOrReduce(getShadow(&I, 1));
+    Value *S = IRB.CreateOr(Shadow0, Shadow1);
+    setShadow(&I, S);
+    setOriginForNaryOp(I);
+  }
+
   // Instrument vector.reduce.or intrinsic.
   // Valid (non-poisoned) set bits in the operand pull low the
   // corresponding shadow bits.
@@ -4344,6 +4356,11 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     case Intrinsic::vector_reduce_mul:
       handleVectorReduceIntrinsic(I);
       break;
+    case Intrinsic::vector_reduce_fadd:
+    case Intrinsic::vector_reduce_fmul:
+      handleVectorReduceWithStarterIntrinsic(I);
+      break;
+
     case Intrinsic::x86_sse_stmxcsr:
       handleStmxcsr(I);
       break;