[PATCH] D42522: [X86] Fix killed flag handling in X86FixupLea pass

[Serguei Katkov via Phabricator via llvm-commits]

skatkov created this revision.
skatkov added reviewers: lsaba, zvi, zansari, aaboud.

When pass creates a MOV instruction for 
lea (%base,%index,1), %dst => mov %base,%dst; add %index,%dst
modification it should clean the killed flag for base if base is equal to index.

Otherwise verifier complains about usage of killed register in add instruction.


https://reviews.llvm.org/D42522

Files:
  lib/Target/X86/X86FixupLEAs.cpp
  test/CodeGen/X86/leaFixup32.mir
  test/CodeGen/X86/leaFixup64.mir


Index: test/CodeGen/X86/leaFixup64.mir
===================================================================
--- test/CodeGen/X86/leaFixup64.mir
+++ test/CodeGen/X86/leaFixup64.mir
@@ -810,7 +810,7 @@
     ; CHECK: %rbx = MOV64rr %rbp
     ; CHECK: %rbx = ADD64rr %rbx, %rbp
  
-    %rbx = LEA64r %rbp, 1, %rbp, 0, %noreg
+    %rbx = LEA64r killed %rbp, 1, %rbp, 0, %noreg
     RETQ %ebx
 
 ...
Index: test/CodeGen/X86/leaFixup32.mir
===================================================================
--- test/CodeGen/X86/leaFixup32.mir
+++ test/CodeGen/X86/leaFixup32.mir
@@ -354,7 +354,7 @@
     ; CHECK: %ebx = MOV32rr  %ebp
     ; CHECK: %ebx = ADD32rr %ebx, %ebp
  
-    %ebx = LEA32r %ebp, 1, %ebp, 0, %noreg
+    %ebx = LEA32r killed %ebp, 1, %ebp, 0, %noreg
     RETQ %ebx
 
 ...
Index: lib/Target/X86/X86FixupLEAs.cpp
===================================================================
--- lib/Target/X86/X86FixupLEAs.cpp
+++ lib/Target/X86/X86FixupLEAs.cpp
@@ -548,7 +548,8 @@
 
   // lea (%base,%index,1), %dst => mov %base,%dst; add %index,%dst
   if (IsScale1 && !hasLEAOffset(Offset)) {
-    TII->copyPhysReg(*MFI, MI, DL, DstR, BaseR, Base.isKill());
+    bool BIK = Base.isKill() && BaseR != IndexR;
+    TII->copyPhysReg(*MFI, MI, DL, DstR, BaseR, BIK);
     DEBUG(MI.getPrevNode()->dump(););
 
     MachineInstr *NewMI =


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