[llvm] 662799c - [DebugInfo][InstrRef] Avoid duplicate instruction numbers in x86-lea-fixup

[Jeremy Morse via llvm-commits]

Author: Jeremy Morse
Date: 2022-02-10T16:36:50Z
New Revision: 662799c8511d345da000fd35e5591ac93a0b88e5

URL: https://github.com/llvm/llvm-project/commit/662799c8511d345da000fd35e5591ac93a0b88e5
DIFF: https://github.com/llvm/llvm-project/commit/662799c8511d345da000fd35e5591ac93a0b88e5.diff

LOG: [DebugInfo][InstrRef] Avoid duplicate instruction numbers in x86-lea-fixup

This new-ish LEA-fixup code path creates two substitutions for an
instruction number -- this is incorrect because each Value should be
replaced by a single replacement Value. Fix by deleting the duplicate
substitution. Add some test coverage for this path with debug-info
attached.

Differential Revision: https://reviews.llvm.org/D119232

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86FixupLEAs.cpp
    llvm/test/DebugInfo/MIR/InstrRef/x86-lea-fixup.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86FixupLEAs.cpp b/llvm/lib/Target/X86/X86FixupLEAs.cpp
index 4730b936ec1fb..c31bc92faf7f1 100644
--- a/llvm/lib/Target/X86/X86FixupLEAs.cpp
+++ b/llvm/lib/Target/X86/X86FixupLEAs.cpp
@@ -546,7 +546,6 @@ bool FixupLEAPass::optLEAALU(MachineBasicBlock::iterator &I,
   if (KilledIndex)
     KilledIndex->setIsKill(false);
 
-  MBB.getParent()->substituteDebugValuesForInst(*AluI, *NewMI1, 1);
   MBB.getParent()->substituteDebugValuesForInst(*AluI, *NewMI2, 1);
   MBB.erase(I);
   MBB.erase(AluI);

diff  --git a/llvm/test/DebugInfo/MIR/InstrRef/x86-lea-fixup.mir b/llvm/test/DebugInfo/MIR/InstrRef/x86-lea-fixup.mir
index 2765ce2284f17..48fe95e36c585 100644
--- a/llvm/test/DebugInfo/MIR/InstrRef/x86-lea-fixup.mir
+++ b/llvm/test/DebugInfo/MIR/InstrRef/x86-lea-fixup.mir
@@ -1,6 +1,6 @@
-# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-gnu-unknown -verify-machineinstrs -mcpu=corei7-avx -o - %s | FileCheck %s --check-prefix=COREI7
-# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-gnu-unknown -verify-machineinstrs -mcpu=haswell -o - %s | FileCheck %s --check-prefix=HASWELL
-# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-unknown-unknown -verify-machineinstrs -mcpu=atom -o - %s | FileCheck %s --check-prefix=ATOM
+# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-gnu-unknown -verify-machineinstrs -mcpu=corei7-avx -o - %s | FileCheck %s --check-prefixes=COREI7,CHECK
+# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-gnu-unknown -verify-machineinstrs -mcpu=haswell -o - %s | FileCheck %s --check-prefixes=HASWELL,CHECK
+# RUN: llc -run-pass x86-fixup-LEAs -mtriple=x86_64-unknown-unknown -verify-machineinstrs -mcpu=atom -o - %s | FileCheck %s --check-prefixes=ATOM,CHECK
 #
 # Test several LEA <=> ADD transformations that the fixup-leas pass performs,
 # and check that any debug-instr-number attached to the original instruction
@@ -9,7 +9,7 @@
 # in this file is only tested by one prefix / CPU mode. Some i386 specific
 # behaviours are in the -2 flavour of this file.
 ---
-# COREI7-LABE: name: pr43758
+# COREI7-LABEL: name: pr43758
 name:            pr43758
 alignment:       16
 tracksRegLiveness: true
@@ -75,3 +75,43 @@ body:             |
     RET64 $eax
 
 ...
+---
+# CHECK-LABEL: testfour
+# In this code sequence, an LEA is converted into a subtract that's combined
+# with another subtract. The instruction number on the computed value should
+# only be attached to the last subtract.
+name:            testfour
+alignment:       16
+tracksRegLiveness: true
+tracksDebugUserValues: true
+liveins:
+  - { reg: '$esi' }
+frameInfo:
+  maxAlignment:    1
+  maxCallFrameSize: 0
+machineFunctionInfo: {}
+# CHECK:      debugValueSubstitutions:
+# CHECK-NEXT:  - { srcinst: 1, srcop: 0, dstinst: 2, dstop: 0, subreg: 0 }
+# CHECK-NEXT: constants:
+body:             |
+  bb.0.entry:
+    liveins: $esi
+
+    $eax = MOV32rr $esi, implicit-def $rax
+
+    renamable $ecx = LEA64_32r renamable $rax, 1, renamable $rax, 0, $noreg
+    renamable $edx = MOV32ri 1
+    renamable $edx = SUB32rr killed renamable $edx, killed renamable $ecx, implicit-def dead $eflags, debug-instr-number 1
+
+    ; CHECK:      MOV32ri 1
+    ; CHECK-NOT:  debug-instr-number
+    ; CHECK-NEXT: SUB32rr
+    ; CHECK-NOT:  debug-instr-number
+    ; CHECK-NEXT: SUB32rr
+    ; CHECK-SAME: debug-instr-number 2
+
+    MOV32mr $noreg, 1, $noreg, 0, $noreg, killed renamable $edx
+    $eax = KILL renamable $eax, implicit killed $rax
+    RET64 $eax
+
+...