[MSAN] Handle x86 {round,min,max}sd intrinsics

These need special handling over the simple vector intrinsics as they
behave more like a shuffle operation: taking the top half of the vector
from one input, and the bottom half separately. Previously, these were
being handled as though all bits of all operands were combined.

Differential Revision: https://reviews.llvm.org/D82398

Author: archshift

llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

@@ -3046,6 +3046,32 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
     SOC.Done(&I);
   }
 
+  // Instrument _mm_*_sd intrinsics
+  void handleUnarySdIntrinsic(IntrinsicInst &I) {
+    IRBuilder<> IRB(&I);
+    Value *First = getShadow(&I, 0);
+    Value *Second = getShadow(&I, 1);
+    // High word of first operand, low word of second
+    Value *Shadow =
+        IRB.CreateShuffleVector(First, Second, llvm::makeArrayRef<int>({2, 1}));
+
+    setShadow(&I, Shadow);
+    setOriginForNaryOp(I);
+  }
+
+  void handleBinarySdIntrinsic(IntrinsicInst &I) {
+    IRBuilder<> IRB(&I);
+    Value *First = getShadow(&I, 0);
+    Value *Second = getShadow(&I, 1);
+    Value *OrShadow = IRB.CreateOr(First, Second);
+    // High word of first operand, low word of both OR'd together
+    Value *Shadow = IRB.CreateShuffleVector(First, OrShadow,
+                                            llvm::makeArrayRef<int>({2, 1}));
+
+    setShadow(&I, Shadow);
+    setOriginForNaryOp(I);
+  }
+
   void visitIntrinsicInst(IntrinsicInst &I) {
     switch (I.getIntrinsicID()) {
     case Intrinsic::lifetime_start:
@@ -3285,6 +3311,14 @@ struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
       handlePclmulIntrinsic(I);
       break;
 
+    case Intrinsic::x86_sse41_round_sd:
+      handleUnarySdIntrinsic(I);
+      break;
+    case Intrinsic::x86_sse2_max_sd:
+    case Intrinsic::x86_sse2_min_sd:
+      handleBinarySdIntrinsic(I);
+      break;
+
     case Intrinsic::is_constant:
       // The result of llvm.is.constant() is always defined.
       setShadow(&I, getCleanShadow(&I));