[X86] PR26575: Fix LEA optimization pass.

Add a missing check for a type of address displacement operand of the load/store instruction being a candidate for LEA substitution.

Ref: https://llvm.org/bugs/show_bug.cgi?id=26575

Differential Revision: http://reviews.llvm.org/D17261

llvm-svn: 260959

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86OptimizeLEAs.cpp b/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
index 9f7de9a8c6a..def49dfbe5c 100644
--- a/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
+++ b/llvm/lib/Target/X86/X86OptimizeLEAs.cpp
@@ -434,6 +434,11 @@ bool OptimizeLEAPass::removeRedundantAddrCalc(MemOpMap &LEAs) {
 
     MemOpNo += X86II::getOperandBias(Desc);
 
+    // Address displacement must be an immediate or a global.
+    MachineOperand &Disp = MI.getOperand(MemOpNo + X86::AddrDisp);
+    if (!Disp.isImm() && !Disp.isGlobal())
+      continue;
+
     // Get the best LEA instruction to replace address calculation.
     MachineInstr *DefMI;
     int64_t AddrDispShift;