[Passes] Remove -enable-infer-alignment-pass flag (#111873)

This flag has been on for a while without any complaints.

Author: aeubanks

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -300,8 +300,6 @@ extern cl::opt<std::string> UseCtxProfile;
 
 namespace llvm {
 extern cl::opt<bool> EnableMemProfContextDisambiguation;
-
-extern cl::opt<bool> EnableInferAlignmentPass;
 } // namespace llvm
 
 PipelineTuningOptions::PipelineTuningOptions() {
@@ -1250,8 +1248,7 @@ void PassBuilder::addVectorPasses(OptimizationLevel Level,
   FPM.addPass(LoopVectorizePass(
       LoopVectorizeOptions(!PTO.LoopInterleaving, !PTO.LoopVectorization)));
 
-  if (EnableInferAlignmentPass)
-    FPM.addPass(InferAlignmentPass());
+  FPM.addPass(InferAlignmentPass());
   if (IsFullLTO) {
     // The vectorizer may have significantly shortened a loop body; unroll
     // again. Unroll small loops to hide loop backedge latency and saturate any
@@ -1369,8 +1366,7 @@ void PassBuilder::addVectorPasses(OptimizationLevel Level,
     FPM.addPass(SROAPass(SROAOptions::PreserveCFG));
   }
 
-  if (EnableInferAlignmentPass)
-    FPM.addPass(InferAlignmentPass());
+  FPM.addPass(InferAlignmentPass());
   FPM.addPass(InstCombinePass());
 
   // This is needed for two reasons:

llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

@@ -37,13 +37,6 @@ static cl::opt<unsigned> MaxCopiedFromConstantUsers(
     cl::desc("Maximum users to visit in copy from constant transform"),
     cl::Hidden);
 
-namespace llvm {
-cl::opt<bool> EnableInferAlignmentPass(
-    "enable-infer-alignment-pass", cl::init(true), cl::Hidden, cl::ZeroOrMore,
-    cl::desc("Enable the InferAlignment pass, disabling alignment inference in "
-             "InstCombine"));
-}
-
 /// isOnlyCopiedFromConstantMemory - Recursively walk the uses of a (derived)
 /// pointer to an alloca.  Ignore any reads of the pointer, return false if we
 /// see any stores or other unknown uses.  If we see pointer arithmetic, keep
@@ -1010,14 +1003,6 @@ Instruction *InstCombinerImpl::visitLoadInst(LoadInst &LI) {
   if (Instruction *Res = combineLoadToOperationType(*this, LI))
     return Res;
 
-  if (!EnableInferAlignmentPass) {
-    // Attempt to improve the alignment.
-    Align KnownAlign = getOrEnforceKnownAlignment(
-        Op, DL.getPrefTypeAlign(LI.getType()), DL, &LI, &AC, &DT);
-    if (KnownAlign > LI.getAlign())
-      LI.setAlignment(KnownAlign);
-  }
-
   // Replace GEP indices if possible.
   if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Op, LI))
     return replaceOperand(LI, 0, NewGEPI);
@@ -1358,14 +1343,6 @@ Instruction *InstCombinerImpl::visitStoreInst(StoreInst &SI) {
   if (combineStoreToValueType(*this, SI))
     return eraseInstFromFunction(SI);
 
-  if (!EnableInferAlignmentPass) {
-    // Attempt to improve the alignment.
-    const Align KnownAlign = getOrEnforceKnownAlignment(
-        Ptr, DL.getPrefTypeAlign(Val->getType()), DL, &SI, &AC, &DT);
-    if (KnownAlign > SI.getAlign())
-      SI.setAlignment(KnownAlign);
-  }
-
   // Try to canonicalize the stored type.
   if (unpackStoreToAggregate(*this, SI))
     return eraseInstFromFunction(SI);