Revert "[SimplifyLibCalls] sprintf doesn't copy null bytes"

The destination buffer that sprintf uses is restrict qualified, we do
not need to worry about derived pointers referenced via format
specifiers.

This reverts commit r267580.

llvm-svn: 267605

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 70f6422..104a82c 100644 (file)
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1995,10 +1995,9 @@ Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI, IRBuilder<> &B) {
     Value *Len = emitStrLen(CI->getArgOperand(2), B, DL, TLI);
     if (!Len)
       return nullptr;
-    B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), Len, 1);
-    Value *PtrToNullByte =
-        B.CreateGEP(B.getInt8Ty(), CI->getArgOperand(0), Len, "nul");
-    B.CreateStore(B.getInt8(0), PtrToNullByte);
+    Value *IncLen =
+        B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");
+    B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
 
     // The sprintf result is the unincremented number of bytes in the string.
     return B.CreateIntCast(Len, CI->getType(), false);

diff --git a/llvm/test/Transforms/InstCombine/sprintf-1.ll b/llvm/test/Transforms/InstCombine/sprintf-1.ll
index 0c7fbcb..ddf2f2f 100644 (file)
--- a/llvm/test/Transforms/InstCombine/sprintf-1.ll
+++ b/llvm/test/Transforms/InstCombine/sprintf-1.ll
@@ -65,9 +65,8 @@ define void @test_simplify5(i8* %dst, i8* %str) {
   %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0
   call i32 (i8*, i8*, ...) @sprintf(i8* %dst, i8* %fmt, i8* %str)
 ; CHECK-NEXT: [[STRLEN:%[a-z0-9]+]] = call i32 @strlen(i8* %str)
-; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %str, i32 [[STRLEN]], i32 1, i1 false)
-; CHECK-NEXT: [[NUL:%[a-z0-9]+]] = getelementptr i8, i8* %dst, i32 [[STRLEN]]
-; CHECK-NEXT: store i8 0, i8* [[NUL]], align 1
+; CHECK-NEXT: [[LENINC:%[a-z0-9]+]] = add i32 [[STRLEN]], 1
+; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %str, i32 [[LENINC]], i32 1, i1 false)
   ret void
 ; CHECK-NEXT: ret void
 }