[llvm-commits] [llvm] r57885 - in /llvm/trunk: lib/CodeGen/SelectionDAG/SelectionDAG.cpp lib/Target/X86/X86ISelLowering.cpp test/CodeGen/X86/x86-64-disp.ll

[Dan Gohman]

Author: djg
Date: Mon Oct 20 22:38:42 2008
New Revision: 57885

URL: http://llvm.org/viewvc/llvm-project?rev=57885&view=rev
Log:
Don't create TargetGlobalAddress nodes with offsets that don't fit
in the 32-bit signed offset field of addresses. Even though this
may be intended, some linkers refuse to relocate code where the
relocated address computation overflows.

Also, fix the sign-extension of constant offsets to use the
actual pointer size, rather than the size of the GlobalAddress
node, which may be different, for example on x86-64 where MVT::i32
is used when the address is being fit into the 32-bit displacement
field.

Added:
    llvm/trunk/test/CodeGen/X86/x86-64-disp.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=57885&r1=57884&r2=57885&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Oct 20 22:38:42 2008
@@ -974,7 +974,7 @@
   unsigned Opc;
 
   // Truncate (with sign-extension) the offset value to the pointer size.
-  unsigned BitWidth = VT.getSizeInBits();
+  unsigned BitWidth = TLI.getPointerTy().getSizeInBits();
   if (BitWidth < 64)
     Offset = (Offset << (64 - BitWidth) >> (64 - BitWidth));
 

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=57885&r1=57884&r2=57885&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Oct 20 22:38:42 2008
@@ -4400,7 +4400,7 @@
   // Create the TargetGlobalAddress node, folding in the constant
   // offset if it is legal.
   SDValue Result;
-  if (!IsPic && !ExtraLoadRequired) {
+  if (!IsPic && !ExtraLoadRequired && isInt32(Offset)) {
     Result = DAG.getTargetGlobalAddress(GV, getPointerTy(), Offset);
     Offset = 0;
   } else

Added: llvm/trunk/test/CodeGen/X86/x86-64-disp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/x86-64-disp.ll?rev=57885&view=auto

==============================================================================
--- llvm/trunk/test/CodeGen/X86/x86-64-disp.ll (added)
+++ llvm/trunk/test/CodeGen/X86/x86-64-disp.ll Mon Oct 20 22:38:42 2008
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep mov | count 2
+
+; Fold an offset into an address even if it's not a 32-bit
+; signed integer.
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+ at call_used_regs = external global [53 x i8], align 32
+
+define fastcc void @foo() nounwind {
+	%t = getelementptr [53 x i8]* @call_used_regs, i64 0, i64 4294967295
+	store i8 1, i8* %t, align 1
+	ret void
+}