[LV] Shrink operands before creating new instr to force eval order.

Shrink operands before creating the new instruction to make sure the
same evaluation order is used on all platforms. This fixes buildbot
failures due to different argument evaluation order on different
systems.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -3595,21 +3595,22 @@ void InnerLoopVectorizer::truncateToMinimalBitwidths(VPTransformState &State) {
       // unfortunately.
       Value *NewI = nullptr;
       if (auto *BO = dyn_cast<BinaryOperator>(I)) {
-        NewI = B.CreateBinOp(BO->getOpcode(), ShrinkOperand(BO->getOperand(0)),
-                             ShrinkOperand(BO->getOperand(1)));
+        Value *Op0 = ShrinkOperand(BO->getOperand(0));
+        Value *Op1 = ShrinkOperand(BO->getOperand(1));
+        NewI = B.CreateBinOp(BO->getOpcode(), Op0, Op1);
 
         // Any wrapping introduced by shrinking this operation shouldn't be
         // considered undefined behavior. So, we can't unconditionally copy
         // arithmetic wrapping flags to NewI.
         cast<BinaryOperator>(NewI)->copyIRFlags(I, /*IncludeWrapFlags=*/false);
       } else if (auto *CI = dyn_cast<ICmpInst>(I)) {
-        NewI =
-            B.CreateICmp(CI->getPredicate(), ShrinkOperand(CI->getOperand(0)),
-                         ShrinkOperand(CI->getOperand(1)));
+        Value *Op0 = ShrinkOperand(BO->getOperand(0));
+        Value *Op1 = ShrinkOperand(BO->getOperand(1));
+        NewI = B.CreateICmp(CI->getPredicate(), Op0, Op1);
       } else if (auto *SI = dyn_cast<SelectInst>(I)) {
-        NewI = B.CreateSelect(SI->getCondition(),
-                              ShrinkOperand(SI->getTrueValue()),
-                              ShrinkOperand(SI->getFalseValue()));
+        Value *TV = ShrinkOperand(SI->getTrueValue());
+        Value *FV = ShrinkOperand(SI->getFalseValue());
+        NewI = B.CreateSelect(SI->getCondition(), TV, FV);
       } else if (auto *CI = dyn_cast<CastInst>(I)) {
         switch (CI->getOpcode()) {
         default: