[llvm-commits] [llvm] r123524 - in /llvm/trunk: lib/Transforms/Scalar/CodeGenPrepare.cpp test/Transforms/CodeGenPrepare/basic.ll

[Chris Lattner]

Author: lattner
Date: Sat Jan 15 01:25:29 2011
New Revision: 123524

URL: http://llvm.org/viewvc/llvm-project?rev=123524&view=rev
Log:
Now that instruction optzns can update the iterator as they go, we can 
have objectsize folding recursively simplify away their result when it
folds.  It is important to catch this here, because otherwise we won't
eliminate the cross-block values at isel and other times.


Added:
    llvm/trunk/test/Transforms/CodeGenPrepare/basic.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp?rev=123524&r1=123523&r2=123524&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/CodeGenPrepare.cpp Sat Jan 15 01:25:29 2011
@@ -42,6 +42,7 @@
 #include "llvm/Support/PatternMatch.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/IRBuilder.h"
+#include "llvm/Support/ValueHandle.h"
 using namespace llvm;
 using namespace llvm::PatternMatch;
 
@@ -634,8 +635,18 @@
     bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
     const Type *ReturnTy = CI->getType();
     Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);    
-    CI->replaceAllUsesWith(RetVal);
-    CI->eraseFromParent();
+    
+    // Substituting this can cause recursive simplifications, which can
+    // invalidate our iterator.  Use a WeakVH to hold onto it in case this
+    // happens.
+    WeakVH IterHandle(CurInstIterator);
+    
+    ReplaceAndSimplifyAllUses(CI, RetVal, TLI ? TLI->getTargetData() : 0, DT);
+
+    // If the iterator instruction was recursively deleted, start over at the
+    // start of the block.
+    if (IterHandle != CurInstIterator)
+      CurInstIterator = BB->begin();
     return true;
   }
 
@@ -653,6 +664,7 @@
   CodeGenPrepareFortifiedLibCalls Simplifier;
   return Simplifier.fold(CI, TD);
 }
+
 //===----------------------------------------------------------------------===//
 // Memory Optimization
 //===----------------------------------------------------------------------===//
@@ -1076,14 +1088,8 @@
   SunkAddrs.clear();
 
   CurInstIterator = BB.begin();
-  for (BasicBlock::iterator E = BB.end(); CurInstIterator != E; ) {
-    Instruction *I = CurInstIterator++;
-
-    if (CallInst *CI = dyn_cast<CallInst>(I))
-      MadeChange |= OptimizeCallInst(CI);
-    else
-      MadeChange |= OptimizeInst(I);
-  }
+  for (BasicBlock::iterator E = BB.end(); CurInstIterator != E; )
+    MadeChange |= OptimizeInst(CurInstIterator++);
 
   return MadeChange;
 }

Added: llvm/trunk/test/Transforms/CodeGenPrepare/basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CodeGenPrepare/basic.ll?rev=123524&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/CodeGenPrepare/basic.ll (added)
+++ llvm/trunk/test/Transforms/CodeGenPrepare/basic.ll Sat Jan 15 01:25:29 2011
@@ -0,0 +1,24 @@
+; RUN: opt -codegenprepare %s -S -o - | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin10.0.0"
+
+; CHECK: @test1
+define i32 @test1(i8* %ptr) nounwind ssp noredzone align 2 {
+entry:
+  %0 = tail call i64 @llvm.objectsize.i64(i8* %ptr, i1 false)
+  %1 = icmp ugt i64 %0, 3
+  br i1 %1, label %T, label %trap
+
+; CHECK: br i1 true, label
+trap:                                             ; preds = %0, %entry
+  tail call void @llvm.trap() noreturn nounwind
+  unreachable
+
+T:
+  ret i32 4
+}
+
+declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly
+
+declare void @llvm.trap() nounwind