[llvm] r205474 - Add comments and test case for [DAG] Keep the opaque constant flag when performing unary constant folding operations (r204737).
Juergen Ributzka
juergen at apple.com
Wed Apr 2 15:21:02 PDT 2014
Author: ributzka
Date: Wed Apr 2 17:21:01 2014
New Revision: 205474
URL: http://llvm.org/viewvc/llvm-project?rev=205474&view=rev
Log:
Add comments and test case for [DAG] Keep the opaque constant flag when performing unary constant folding operations (r204737).
Added:
llvm/trunk/test/CodeGen/X86/const-base-addr.ll
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=205474&r1=205473&r2=205474&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Wed Apr 2 17:21:01 2014
@@ -2535,7 +2535,11 @@ SDValue SelectionDAG::getNode(unsigned O
SDValue SelectionDAG::getNode(unsigned Opcode, SDLoc DL,
EVT VT, SDValue Operand) {
- // Constant fold unary operations with an integer constant operand.
+ // Constant fold unary operations with an integer constant operand. Even
+ // opaque constant will be folded, because the folding of unary operations
+ // doesn't create new constants with different values. Nevertheless, the
+ // opaque flag is preserved during folding to prevent future folding with
+ // other constants.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Operand.getNode())) {
const APInt &Val = C->getAPIntValue();
switch (Opcode) {
Added: llvm/trunk/test/CodeGen/X86/const-base-addr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/const-base-addr.ll?rev=205474&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/const-base-addr.ll (added)
+++ llvm/trunk/test/CodeGen/X86/const-base-addr.ll Wed Apr 2 17:21:01 2014
@@ -0,0 +1,24 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.9.0"
+
+%T = type { i32, i32, i32, i32 }
+
+define i32 @test1() nounwind {
+; CHECK-LABEL: test1
+; CHECK: movabsq $123456789012345678, %rcx
+; CHECK-NEXT: movl 4(%rcx), %eax
+; CHECK-NEXT: addl 8(%rcx), %eax
+; CHECK-NEXT: addl 12(%rcx), %eax
+ %addr1 = getelementptr %T* inttoptr (i64 123456789012345678 to %T*), i32 0, i32 1
+ %tmp1 = load i32* %addr1
+ %addr2 = getelementptr %T* inttoptr (i64 123456789012345678 to %T*), i32 0, i32 2
+ %tmp2 = load i32* %addr2
+ %addr3 = getelementptr %T* inttoptr (i64 123456789012345678 to %T*), i32 0, i32 3
+ %tmp3 = load i32* %addr3
+ %tmp4 = add i32 %tmp1, %tmp2
+ %tmp5 = add i32 %tmp3, %tmp4
+ ret i32 %tmp5
+}
+
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