Make MemoryBuiltins aware of TargetLibraryInfo.

This disables malloc-specific optimization when -fno-builtin (or -ffreestanding)
is specified. This has been a problem for a long time but became more severe
with the recent memory builtin improvements.

Since the memory builtin functions are used everywhere, this required passing
TLI in many places. This means that functions that now have an optional TLI
argument, like RecursivelyDeleteTriviallyDeadFunctions, won't remove dead
mallocs anymore if the TLI argument is missing. I've updated most passes to do
the right thing.

Fixes PR13694 and probably others.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162841 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/lib/Transforms/Scalar/DCE.cpp b/lib/Transforms/Scalar/DCE.cpp
index 8dbcc23..086f0a1 100644
--- a/lib/Transforms/Scalar/DCE.cpp
+++ b/lib/Transforms/Scalar/DCE.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Instruction.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/InstIterator.h"
+#include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/ADT/Statistic.h"
 using namespace llvm;
 
@@ -38,10 +39,11 @@ namespace {
       initializeDeadInstEliminationPass(*PassRegistry::getPassRegistry());
     }
     virtual bool runOnBasicBlock(BasicBlock &BB) {
+      TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
       bool Changed = false;
       for (BasicBlock::iterator DI = BB.begin(); DI != BB.end(); ) {
         Instruction *Inst = DI++;
-        if (isInstructionTriviallyDead(Inst)) {
+        if (isInstructionTriviallyDead(Inst, TLI)) {
           Inst->eraseFromParent();
           Changed = true;
           ++DIEEliminated;
@@ -87,6 +89,8 @@ char DCE::ID = 0;
 INITIALIZE_PASS(DCE, "dce", "Dead Code Elimination", false, false)
 
 bool DCE::runOnFunction(Function &F) {
+  TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
+
   // Start out with all of the instructions in the worklist...
   std::vector<Instruction*> WorkList;
   for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
@@ -101,7 +105,7 @@ bool DCE::runOnFunction(Function &F) {
     Instruction *I = WorkList.back();
     WorkList.pop_back();
 
-    if (isInstructionTriviallyDead(I)) {       // If the instruction is dead.
+    if (isInstructionTriviallyDead(I, TLI)) { // If the instruction is dead.
       // Loop over all of the values that the instruction uses, if there are
       // instructions being used, add them to the worklist, because they might
       // go dead after this one is removed.