fix PR5104: when printing a single character, return the result of

putchar in case there is an error.

llvm-svn: 86515

1 files changed, 13 insertions, 9 deletions

diff --git a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index ecca3c73b90..296f0c9ac54 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -100,7 +100,7 @@ public:
 
   /// EmitPutChar - Emit a call to the putchar function.  This assumes that Char
   /// is an integer.
-  void EmitPutChar(Value *Char, IRBuilder<> &B);
+  Value *EmitPutChar(Value *Char, IRBuilder<> &B);
 
   /// EmitPutS - Emit a call to the puts function.  This assumes that Str is
   /// some pointer.
@@ -252,7 +252,7 @@ Value *LibCallOptimization::EmitUnaryFloatFnCall(Value *Op, const char *Name,
 
 /// EmitPutChar - Emit a call to the putchar function.  This assumes that Char
 /// is an integer.
-void LibCallOptimization::EmitPutChar(Value *Char, IRBuilder<> &B) {
+Value *LibCallOptimization::EmitPutChar(Value *Char, IRBuilder<> &B) {
   Module *M = Caller->getParent();
   Value *PutChar = M->getOrInsertFunction("putchar", Type::getInt32Ty(*Context),
                                           Type::getInt32Ty(*Context), NULL);
@@ -264,6 +264,7 @@ void LibCallOptimization::EmitPutChar(Value *Char, IRBuilder<> &B) {
 
   if (const Function *F = dyn_cast<Function>(PutChar->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
+  return CI;
 }
 
 /// EmitPutS - Emit a call to the puts function.  This assumes that Str is
@@ -1325,11 +1326,13 @@ struct PrintFOpt : public LibCallOptimization {
       return CI->use_empty() ? (Value*)CI :
                                ConstantInt::get(CI->getType(), 0);
 
-    // printf("x") -> putchar('x'), even for '%'.
+    // printf("x") -> putchar('x'), even for '%'.  Return the result of putchar
+    // in case there is an error writing to stdout.
     if (FormatStr.size() == 1) {
-      EmitPutChar(ConstantInt::get(Type::getInt32Ty(*Context), FormatStr[0]), B);
-      return CI->use_empty() ? (Value*)CI :
-                               ConstantInt::get(CI->getType(), 1);
+      Value *Res = EmitPutChar(ConstantInt::get(Type::getInt32Ty(*Context),
+                                                FormatStr[0]), B);
+      if (CI->use_empty()) return CI;
+      return B.CreateIntCast(Res, CI->getType(), true);
     }
 
     // printf("foo\n") --> puts("foo")
@@ -1350,9 +1353,10 @@ struct PrintFOpt : public LibCallOptimization {
     // printf("%c", chr) --> putchar(*(i8*)dst)
     if (FormatStr == "%c" && CI->getNumOperands() > 2 &&
         isa<IntegerType>(CI->getOperand(2)->getType())) {
-      EmitPutChar(CI->getOperand(2), B);
-      return CI->use_empty() ? (Value*)CI :
-                               ConstantInt::get(CI->getType(), 1);
+      Value *Res = EmitPutChar(CI->getOperand(2), B);
+      
+      if (CI->use_empty()) return CI;
+      return B.CreateIntCast(Res, CI->getType(), true);
     }
 
     // printf("%s\n", str) --> puts(str)