[llvm] r294098 - [IPCP] Don't propagate return value for naked functions.

[Davide Italiano via llvm-commits]

Author: davide
Date: Sat Feb  4 13:44:14 2017
New Revision: 294098

URL: http://llvm.org/viewvc/llvm-project?rev=294098&view=rev
Log:
[IPCP] Don't propagate return value for naked functions.

This is pretty much the same change made in SCCP.

Modified:
    llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp
    llvm/trunk/test/Transforms/IPConstantProp/naked-return.ll

Modified: llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp?rev=294098&r1=294097&r2=294098&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp Sat Feb  4 13:44:14 2017
@@ -136,7 +136,13 @@ static bool PropagateConstantReturn(Func
   // For more details, see GlobalValue::mayBeDerefined.
   if (!F.isDefinitionExact())
     return false;
-    
+
+  // Don't touch naked functions. The may contain asm returning
+  // value we don't see, so we may end up interprocedurally propagating
+  // the return value incorrectly.
+  if (F.hasFnAttribute(Attribute::Naked))
+    return false;
+
   // Check to see if this function returns a constant.
   SmallVector<Value *,4> RetVals;
   StructType *STy = dyn_cast<StructType>(F.getReturnType());

Modified: llvm/trunk/test/Transforms/IPConstantProp/naked-return.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IPConstantProp/naked-return.ll?rev=294098&r1=294097&r2=294098&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/IPConstantProp/naked-return.ll (original)
+++ llvm/trunk/test/Transforms/IPConstantProp/naked-return.ll Sat Feb  4 13:44:14 2017
@@ -1,4 +1,5 @@
 ; RUN: opt -ipsccp -S %s | FileCheck %s
+; RUN: opt -ipconstprop -S %s | FileCheck %s
 
 target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
 target triple = "i686-pc-windows-msvc19.0.24215"