Revert "[InstCombine] snprintf optimizations"

This reverts commit r331849. It miscompiles
snprintf(buf, sizeof(buf), "%s", "any constant string); into
memcpy(buf, "%s", sizeof("any constant string"));

llvm-svn: 331866

1 files changed, 0 insertions, 90 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index a645433f62f..ce804aef7da 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1912,94 +1912,6 @@ Value *LibCallSimplifier::optimizeSPrintF(CallInst *CI, IRBuilder<> &B) {
   return nullptr;
 }
 
-Value *LibCallSimplifier::optimizeSnPrintFString(CallInst *CI, IRBuilder<> &B) {
-  // Check for a fixed format string.
-  StringRef FormatStr;
-  if (!getConstantStringInfo(CI->getArgOperand(2), FormatStr))
-    return nullptr;
-
-  // Check for size
-  ConstantInt *Size = dyn_cast<ConstantInt>(CI->getArgOperand(1));
-  if (!Size)
-    return nullptr;
-
-  uint64_t N = Size->getZExtValue();
-
-  // If we just have a format string (nothing else crazy) transform it.
-  if (CI->getNumArgOperands() == 3) {
-    // Make sure there's no % in the constant array.  We could try to handle
-    // %% -> % in the future if we cared.
-    for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
-      if (FormatStr[i] == '%')
-        return nullptr; // we found a format specifier, bail out.
-
-    if (N == 0)
-      return ConstantInt::get(CI->getType(), FormatStr.size());
-    else if (N < FormatStr.size() + 1)
-      return nullptr;
-
-    // sprintf(str, size, fmt) -> llvm.memcpy(align 1 str, align 1 fmt,
-    // strlen(fmt)+1)
-    B.CreateMemCpy(
-        CI->getArgOperand(0), 1, CI->getArgOperand(2), 1,
-        ConstantInt::get(DL.getIntPtrType(CI->getContext()),
-                         FormatStr.size() + 1)); // Copy the null byte.
-    return ConstantInt::get(CI->getType(), FormatStr.size());
-  }
-
-  // The remaining optimizations require the format string to be "%s" or "%c"
-  // and have an extra operand.
-  if (FormatStr.size() == 2 && FormatStr[0] == '%' &&
-      CI->getNumArgOperands() == 4) {
-
-    // Decode the second character of the format string.
-    if (FormatStr[1] == 'c') {
-      if (N == 0)
-        return ConstantInt::get(CI->getType(), 1);
-      else if (N == 1)
-        return nullptr;
-
-      // snprintf(dst, size, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
-      if (!CI->getArgOperand(3)->getType()->isIntegerTy())
-        return nullptr;
-      Value *V = B.CreateTrunc(CI->getArgOperand(3), B.getInt8Ty(), "char");
-      Value *Ptr = castToCStr(CI->getArgOperand(0), B);
-      B.CreateStore(V, Ptr);
-      Ptr = B.CreateGEP(B.getInt8Ty(), Ptr, B.getInt32(1), "nul");
-      B.CreateStore(B.getInt8(0), Ptr);
-
-      return ConstantInt::get(CI->getType(), 1);
-    }
-
-    if (FormatStr[1] == 's') {
-      // snprintf(dest, size, "%s", str) to llvm.memcpy(dest, str, len+1, 1)
-      StringRef Str;
-      if (!getConstantStringInfo(CI->getArgOperand(3), Str))
-        return nullptr;
-
-      if (N == 0)
-        return ConstantInt::get(CI->getType(), Str.size());
-      else if (N < Str.size() + 1)
-        return nullptr;
-
-      B.CreateMemCpy(CI->getArgOperand(0), 1, CI->getArgOperand(2), 1,
-                     ConstantInt::get(CI->getType(), Str.size() + 1));
-
-      // The snprintf result is the unincremented number of bytes in the string.
-      return ConstantInt::get(CI->getType(), Str.size());
-    }
-  }
-  return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeSnPrintF(CallInst *CI, IRBuilder<> &B) {
-  if (Value *V = optimizeSnPrintFString(CI, B)) {
-    return V;
-  }
-
-  return nullptr;
-}
-
 Value *LibCallSimplifier::optimizeFPrintFString(CallInst *CI, IRBuilder<> &B) {
   optimizeErrorReporting(CI, B, 0);
 
@@ -2406,8 +2318,6 @@ Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
       return optimizePrintF(CI, Builder);
     case LibFunc_sprintf:
       return optimizeSPrintF(CI, Builder);
-    case LibFunc_snprintf:
-      return optimizeSnPrintF(CI, Builder);
     case LibFunc_fprintf:
       return optimizeFPrintF(CI, Builder);
     case LibFunc_fwrite: