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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57885 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 2ad3da038771ccf1951ac4a41bf1d5235370e061..7c70cd4d72d563888d5ea25a5bc1eb5d401c2c82 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -974,7 +974,7 @@ SDValue SelectionDAG::getGlobalAddress(const GlobalValue *GV,
   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));
 

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index ebf9eecf208e7e40d0d1f5e01057057baa4dddcf..eee38406505566d48e408fb9a510a0ed4526c581 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4400,7 +4400,7 @@ X86TargetLowering::LowerGlobalAddress(const GlobalValue *GV,
   // 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

diff --git a/test/CodeGen/X86/x86-64-disp.ll b/test/CodeGen/X86/x86-64-disp.ll
new file mode 100644 (file)
index 0000000..4a8f6cd
--- /dev/null
+++ b/test/CodeGen/X86/x86-64-disp.ll
@@ -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"
+@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
+}