[llvm-commits] [llvm] r82700 - in /llvm/trunk: lib/Transforms/IPO/IPConstantPropagation.cpp lib/Transforms/Scalar/SCCP.cpp test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll

Torok Edwin edwintorok at gmail.com
Thu Sep 24 13:33:43 CDT 2009


Author: edwin
Date: Thu Sep 24 13:33:42 2009
New Revision: 82700

URL: http://llvm.org/viewvc/llvm-project?rev=82700&view=rev
Log:
Constant propagating byval pointer is safe if function is readonly.

Modified:
    llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp
    llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
    llvm/trunk/test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll

Modified: llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp?rev=82700&r1=82699&r2=82700&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/IPConstantPropagation.cpp Thu Sep 24 13:33:42 2009
@@ -130,8 +130,8 @@
   Function::arg_iterator AI = F.arg_begin();
   for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI) {
     // Do we have a constant argument?
-    if (ArgumentConstants[i].second || AI->use_empty() || 
-        (AI->hasByValAttr() && isa<PointerType>(AI->getType())))
+    if (ArgumentConstants[i].second || AI->use_empty() ||
+        (AI->hasByValAttr() && !F.onlyReadsMemory()))
       continue;
   
     Value *V = ArgumentConstants[i].first;

Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=82700&r1=82699&r2=82700&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Thu Sep 24 13:33:42 2009
@@ -1267,7 +1267,7 @@
   for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
        AI != E; ++AI, ++CAI) {
     LatticeVal &IV = ValueState[AI];
-    if (AI->hasByValAttr() && isa<PointerType>(AI->getType())) {
+    if (AI->hasByValAttr() && !F->onlyReadsMemory()) {
       IV.markOverdefined();
       continue;
     }

Modified: llvm/trunk/test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll?rev=82700&r1=82699&r2=82700&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll (original)
+++ llvm/trunk/test/Transforms/IPConstantProp/2009-09-24-byval-ptr.ll Thu Sep 24 13:33:42 2009
@@ -16,9 +16,25 @@
 return:                                           ; preds = %entry
   ret void
 }
-define void @unions() nounwind {
+
+define internal i32 @vfu2(%struct.MYstr* byval align 4 %u) nounwind readonly {
+entry:
+  %0 = getelementptr %struct.MYstr* %u, i32 0, i32 1 ; <i32*> [#uses=1]
+  %1 = load i32* %0
+; CHECK: load i32* getelementptr inbounds (%struct.MYstr* @mystr, i32 0, i32 1) ; <i32> [#uses=1]
+  %2 = getelementptr %struct.MYstr* %u, i32 0, i32 0 ; <i8*> [#uses=1]
+  %3 = load i8* %2
+; CHECK: load i8* getelementptr inbounds (%struct.MYstr* @mystr, i32 0, i32 0) ; <i8> [#uses=1]
+  %4 = zext i8 %3 to i32
+  %5 = add i32 %4, %1
+  ret i32 %5
+}
+
+define i32 @unions() nounwind {
 entry:
   call void @vfu1(%struct.MYstr* byval align 4 @mystr) nounwind
-  ret void
+  %result = call i32 @vfu2(%struct.MYstr* byval align 4 @mystr) nounwind
+
+  ret i32 %result
 }
 





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