[llvm-commits] [llvm] r84941 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/Transforms/ConstProp/loads.ll

[Chris Lattner]

Author: lattner
Date: Fri Oct 23 01:50:36 2009
New Revision: 84941

URL: http://llvm.org/viewvc/llvm-project?rev=84941&view=rev
Log:
enhance FoldReinterpretLoadFromConstPtr to handle loads of up to 32 
bytes (i256).

Modified:
    llvm/trunk/lib/Analysis/ConstantFolding.cpp
    llvm/trunk/test/Transforms/ConstProp/loads.ll

Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=84941&r1=84940&r2=84941&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Fri Oct 23 01:50:36 2009
@@ -232,7 +232,7 @@
   }
   
   unsigned BytesLoaded = (IntType->getBitWidth() + 7) / 8;
-  if (BytesLoaded > 8 || BytesLoaded == 0) return 0;
+  if (BytesLoaded > 32 || BytesLoaded == 0) return 0;
   
   GlobalValue *GVal;
   int64_t Offset;
@@ -253,16 +253,18 @@
   if (uint64_t(Offset) >= TD.getTypeAllocSize(GV->getInitializer()->getType()))
     return UndefValue::get(IntType);
   
-  unsigned char RawBytes[8] = {0};
+  unsigned char RawBytes[32] = {0};
   if (!ReadDataFromGlobal(GV->getInitializer(), Offset, RawBytes,
                           BytesLoaded, TD))
     return 0;
 
-  uint64_t ResultVal = 0;
-  for (unsigned i = 0; i != BytesLoaded; ++i)
-    ResultVal |= (uint64_t)RawBytes[i] << (i * 8);
+  APInt ResultVal(IntType->getBitWidth(), 0);
+  for (unsigned i = 0; i != BytesLoaded; ++i) {
+    ResultVal <<= 8;
+    ResultVal |= APInt(IntType->getBitWidth(), RawBytes[BytesLoaded-1-i]);
+  }
 
-  return ConstantInt::get(IntType, ResultVal);
+  return ConstantInt::get(IntType->getContext(), ResultVal);
 }
 
 /// ConstantFoldLoadFromConstPtr - Return the value that a load from C would

Modified: llvm/trunk/test/Transforms/ConstProp/loads.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstProp/loads.ll?rev=84941&r1=84940&r2=84941&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/ConstProp/loads.ll (original)
+++ llvm/trunk/test/Transforms/ConstProp/loads.ll Fri Oct 23 01:50:36 2009
@@ -4,6 +4,7 @@
 
 @test1 = constant {{i32,i8},i32} {{i32,i8} { i32 -559038737, i8 186 }, i32 -889275714 }
 @test2 = constant double 1.0
+ at test3 = constant {i64, i64} { i64 123, i64 112312312 }
 
 ; Simple load
 define i32 @test1() {
@@ -66,3 +67,13 @@
 ; @test8
 ; CHECK: ret double 0xDEADBEBA
 }
+
+
+; i128 load.
+define i128 @test9() {
+  %r = load i128* bitcast({i64, i64}* @test3 to i128*)
+  ret i128 %r
+
+; @test9
+; CHECK: ret i128 112312312
+}