From 1a3c2c414ca7f9cbd54778fca0e333edd3d45b94 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Tue, 25 Nov 2014 08:20:27 +0000
Subject: Revert r220349 to re-instate r220277 with a fix for PR21330 -- quite
 clearly only exactly equal width ptrtoint and inttoptr casts are no-op casts,
 it says so right there in the langref. Make the code agree.

Original log from r220277:
Teach the load analysis to allow finding available values which require
inttoptr or ptrtoint cast provided there is datalayout available.
Eventually, the datalayout can just be required but in practice it will
always be there today.

To go with the ability to expose available values requiring a ptrtoint
or inttoptr cast, helpers are added to perform one of these three casts.

These smarts are necessary to finish canonicalizing loads and stores to
the operational type requirements without regressing fundamental
combines.

I've added some test cases. These should actually improve as the load
combining and store combining improves, but they may fundamentally be
highlighting some missing combines for select in addition to exercising
the specific added logic to load analysis.

llvm-svn: 222739
---
 llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp | 3 ++-
 llvm/lib/Transforms/Scalar/JumpThreading.cpp                   | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

(limited to 'llvm/lib/Transforms')

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index f3ac44cbd6b..c0df914cb66 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -418,7 +418,8 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   BasicBlock::iterator BBI = &LI;
   if (Value *AvailableVal = FindAvailableLoadedValue(Op, LI.getParent(), BBI,6))
     return ReplaceInstUsesWith(
-        LI, Builder->CreateBitCast(AvailableVal, LI.getType()));
+        LI, Builder->CreateBitOrPointerCast(AvailableVal, LI.getType(),
+                                            LI.getName() + ".cast"));
 
   // load(gep null, ...) -> unreachable
   if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op)) {
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 60a4925eeb1..ba165bdcde4 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -902,8 +902,8 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) {
     // only happen in dead loops.
     if (AvailableVal == LI) AvailableVal = UndefValue::get(LI->getType());
     if (AvailableVal->getType() != LI->getType())
-      AvailableVal = CastInst::Create(CastInst::BitCast, AvailableVal,
-                                      LI->getType(), "", LI);
+      AvailableVal =
+          CastInst::CreateBitOrPointerCast(AvailableVal, LI->getType(), "", LI);
     LI->replaceAllUsesWith(AvailableVal);
     LI->eraseFromParent();
     return true;
@@ -1040,8 +1040,8 @@ bool JumpThreading::SimplifyPartiallyRedundantLoad(LoadInst *LI) {
     // predecessor use the same bitcast.
     Value *&PredV = I->second;
     if (PredV->getType() != LI->getType())
-      PredV = CastInst::Create(CastInst::BitCast, PredV, LI->getType(), "",
-                               P->getTerminator());
+      PredV = CastInst::CreateBitOrPointerCast(PredV, LI->getType(), "",
+                                               P->getTerminator());
 
     PN->addIncoming(PredV, I->first);
   }
-- 
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