[llvm] 04a2d50 - [PPC] Use getSignedConstant() for frame index offset

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2024-11-28T10:49:45+01:00
New Revision: 04a2d50efd668b752718f90811a7c628bfa761d7

URL: https://github.com/llvm/llvm-project/commit/04a2d50efd668b752718f90811a7c628bfa761d7
DIFF: https://github.com/llvm/llvm-project/commit/04a2d50efd668b752718f90811a7c628bfa761d7.diff

LOG: [PPC] Use getSignedConstant() for frame index offset

The offset is signed. Fixes assertion failure reported at:
https://github.com/llvm/llvm-project/pull/117558#issuecomment-2504413074

Added: 
    llvm/test/CodeGen/PowerPC/frameindex-negative-offset.ll

Modified: 
    llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 4706051e601569..2475b8ad11f10a 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -193,8 +193,8 @@ namespace {
     }
 
     /// getSmallIPtrImm - Return a target constant of pointer type.
-    inline SDValue getSmallIPtrImm(uint64_t Imm, const SDLoc &dl) {
-      return CurDAG->getTargetConstant(
+    inline SDValue getSmallIPtrImm(int64_t Imm, const SDLoc &dl) {
+      return CurDAG->getSignedTargetConstant(
           Imm, dl, PPCLowering->getPointerTy(CurDAG->getDataLayout()));
     }
 
@@ -207,7 +207,7 @@ namespace {
     /// base register.  Return the virtual register that holds this value.
     SDNode *getGlobalBaseReg();
 
-    void selectFrameIndex(SDNode *SN, SDNode *N, uint64_t Offset = 0);
+    void selectFrameIndex(SDNode *SN, SDNode *N, int64_t Offset = 0);
 
     // Select - Convert the specified operand from a target-independent to a
     // target-specific node if it hasn't already been changed.
@@ -639,7 +639,7 @@ static bool isOpcWithIntImmediate(SDNode *N, unsigned Opc, unsigned& Imm) {
          && isInt32Immediate(N->getOperand(1).getNode(), Imm);
 }
 
-void PPCDAGToDAGISel::selectFrameIndex(SDNode *SN, SDNode *N, uint64_t Offset) {
+void PPCDAGToDAGISel::selectFrameIndex(SDNode *SN, SDNode *N, int64_t Offset) {
   SDLoc dl(SN);
   int FI = cast<FrameIndexSDNode>(N)->getIndex();
   SDValue TFI = CurDAG->getTargetFrameIndex(FI, N->getValueType(0));

diff  --git a/llvm/test/CodeGen/PowerPC/frameindex-negative-offset.ll b/llvm/test/CodeGen/PowerPC/frameindex-negative-offset.ll
new file mode 100644
index 00000000000000..c2208bba31aefd
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/frameindex-negative-offset.ll
@@ -0,0 +1,14 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=powerpc-unknown-linux-gnu < %s | FileCheck %s
+
+define ptr @test() nounwind {
+; CHECK-LABEL: test:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    stwu 1, -16(1)
+; CHECK-NEXT:    addi 3, 1, 10
+; CHECK-NEXT:    addi 1, 1, 16
+; CHECK-NEXT:    blr
+  %alloca = alloca i32
+  %gep = getelementptr i8, ptr %alloca, i32 -2
+  ret ptr %gep
+}