[llvm] [InstrRef] Skip clobbered EntryValue register recovery (PR #142478)

[Jeremy Morse via llvm-commits]

================
@@ -0,0 +1,91 @@
+# RUN: llc --run-pass=livedebugvalues -o - %s | FileCheck %s
+# REQUIRES: x86-registered-target
+--- |
+  target triple = "x86_64-"
+
+  define i32 @baz(i32 swiftasync %arg1, i32 noundef %arg2, i1 %cond) !dbg !9 {
+    tail call void @llvm.dbg.value(metadata i32 %arg1, metadata !17, metadata !DIExpression(DW_OP_LLVM_entry_value, 1)), !dbg !19
+    br i1 %cond, label %if.then, label %if.else, !dbg !22
+  if.then:
+    %call = call i32 @foo(i32 noundef %arg1), !dbg !23
+    br label %if.end, !dbg !25
+  if.else:
+    %call1 = call i32 @foo(i32 noundef %arg2), !dbg !26
+    br label %if.end
+  if.end:
+    %temp.0 = phi i32 [ %call, %if.then ], [ %call1, %if.else ], !dbg !28
+    ret i32 %temp.0, !dbg !29
+  }
+
+  declare i32 @foo(i32)
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!2, !3}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "ha", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+  !1 = !DIFile(filename: "test.c", directory: "hah")
+  !2 = !{i32 7, !"Dwarf Version", i32 4}
+  !3 = !{i32 2, !"Debug Info Version", i32 3}
+  !9 = distinct !DISubprogram(name: "baz", scope: !1, file: !1, line: 3, type: !10, scopeLine: 3, unit: !0, retainedNodes: !13)
+  !10 = !DISubroutineType(types: !11)
+  !11 = !{!12, !12, !12, !12}
+  !12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+  !13 = !{!14, !15, !16, !17}
+  !14 = !DILocalVariable(name: "arg1", arg: 1, scope: !9, file: !1, line: 3, type: !12)
+  !15 = !DILocalVariable(name: "arg2", arg: 2, scope: !9, file: !1, line: 3, type: !12)
+  !16 = !DILocalVariable(name: "cond", arg: 3, scope: !9, file: !1, line: 3, type: !12)
+  !17 = !DILocalVariable(name: "local", scope: !9, file: !1, line: 4, type: !12)
+  !19 = !DILocation(line: 0, scope: !9)
+  !20 = !DILocation(line: 7, column: 7, scope: !21)
+  !21 = distinct !DILexicalBlock(scope: !9, file: !1, line: 7, column: 7)
+  !22 = !DILocation(line: 7, column: 7, scope: !9)
+  !23 = !DILocation(line: 8, column: 12, scope: !24)
+  !24 = distinct !DILexicalBlock(scope: !21, file: !1, line: 7, column: 13)
+  !25 = !DILocation(line: 9, column: 3, scope: !24)
+  !26 = !DILocation(line: 10, column: 12, scope: !27)
+  !27 = distinct !DILexicalBlock(scope: !21, file: !1, line: 9, column: 10)
+  !28 = !DILocation(line: 0, scope: !21)
+  !29 = !DILocation(line: 13, column: 3, scope: !9)
+
+...
+---
+name:            baz
+alignment:       16
+debugInstrRef: true
+tracksDebugUserValues: true
+liveins:
+  - { reg: '$r14', virtual-reg: '' }
+  - { reg: '$edi', virtual-reg: '' }
+  - { reg: '$esi', virtual-reg: '' }
+  - { reg: '$edx', virtual-reg: '' }
+body:             |
+  bb.0:
+    successors: %bb.2(0x40000000), %bb.1(0x40000000)
+    liveins: $r14, $edi, $edx, $esi
+    DBG_VALUE $r14, $noreg, !14, !DIExpression(DW_OP_LLVM_entry_value, 1), debug-location !19
+    $r14 = MOV64ri 0, debug-location !20
+    CMP32ri killed renamable $edx, 0, implicit-def $eflags, debug-location !20
+    JCC_1 %bb.2, 4, implicit killed $eflags, debug-location !22
+  bb.1.if.then:
+    successors: %bb.3(0x80000000)
+    liveins: $edi, $r13
+    CALL64pcrel32 @foo, csr_64, implicit $rsp, implicit $ssp, implicit $edi, implicit-def $eax, debug-location !23
----------------
jmorse wrote:

Stick r14 clobber here? (see main comment).

https://github.com/llvm/llvm-project/pull/142478