[LiveDebugVariables] Stop trimming locations of non-inlined vars

The D35953, D62650 and D73691 introduced trimming of variables locations
in LiveDebugVariables pass, since there are some cases where after
the virtregrewrite we have exploded number of DBG_VALUEs created for some
inlined variables. As it looks, all problematic cases were regarding
inlined variables, so it seems reasonable to stop trimming the location
ranges for non-inlined variables.
It has very good impact on the llvm-locstats report.

Differential Revision: https://reviews.llvm.org/D102917

llvm/lib/CodeGen/LiveDebugVariables.cpp

@@ -1154,7 +1154,11 @@ void UserValue::computeIntervals(MachineRegisterInfo &MRI,
   // location's lexical scope. In this case, splitting of an interval
   // can result in an interval outside of the scope being created,
   // causing extra unnecessary DBG_VALUEs to be emitted. To prevent
-  // this, trim the intervals to the lexical scope.
+  // this, trim the intervals to the lexical scope in the case of inlined
+  // variables, since heavy inlining may cause production of dramatically big
+  // number of DBG_VALUEs to be generated.
+  if (!dl.getInlinedAt())
+    return;
 
   LexicalScope *Scope = LS.findLexicalScope(dl);
   if (!Scope)

llvm/test/CodeGen/AMDGPU/ptr-arg-dbg-value.ll

@@ -14,10 +14,10 @@ define hidden void @ptr_arg_split_subregs(%struct.A* %arg1) #0 !dbg !9 {
 ; CHECK-NEXT:    .cfi_startproc
 ; CHECK-NEXT:  ; %bb.0:
 ; CHECK-NEXT:    ;DEBUG_VALUE: ptr_arg_split_subregs:a <- [DW_OP_LLVM_fragment 32 32] [$vgpr1+0]
+; CHECK-NEXT:    ;DEBUG_VALUE: ptr_arg_split_subregs:a <- [DW_OP_LLVM_fragment 0 32] [$vgpr0+0]
 ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; CHECK-NEXT:    v_mov_b32_e32 v2, 1
 ; CHECK-NEXT:  .Ltmp0:
-; CHECK-NEXT:    ;DEBUG_VALUE: ptr_arg_split_subregs:a <- [DW_OP_LLVM_fragment 0 32] [$vgpr0+0]
 ; CHECK-NEXT:    .loc 1 7 13 prologue_end ; example.cpp:7:13
 ; CHECK-NEXT:    flat_store_dword v[0:1], v2 offset:396
 ; CHECK-NEXT:    .loc 1 8 5 ; example.cpp:8:5

llvm/test/CodeGen/PowerPC/non-debug-mi-search-frspxsrsp.ll

@@ -5,14 +5,14 @@ define dso_local void @test(float* nocapture readonly %Fptr, <4 x float>* nocapt
 ; CHECK-LABEL: test:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:          #DEBUG_VALUE: test:Fptr <- $x3
+; CHECK-NEXT:          #DEBUG_VALUE: test:Fptr <- $x3
 ; CHECK-NEXT:          #DEBUG_VALUE: test:Vptr <- $x4
 ; CHECK-NEXT:          addis 5, 2, .LCPI0_0@toc@ha
 ; CHECK-NEXT:  .Ltmp0:
 ; CHECK-NEXT:          .loc    1 2 38 prologue_end
 ; CHECK-NEXT:          lfsx 0, 0, 3
 ; CHECK-NEXT:          addis 3, 2, .LCPI0_1@toc@ha
 ; CHECK-NEXT:  .Ltmp1:
-; CHECK-NEXT:          #DEBUG_VALUE: test:Fptr <- $x3
 ; CHECK-NEXT:          .loc    1 0 38 is_stmt 0
 ; CHECK-NEXT:          lfs 1, .LCPI0_0@toc@l(5)
 ; CHECK-NEXT:          lfd 2, .LCPI0_1@toc@l(3)

llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir

@@ -0,0 +1,119 @@
+# RUN: llc -run-pass=greedy -run-pass=virtregrewriter %s -o - | FileCheck %s
+
+## This tests that LiveDebugVariables does not trim non-inlined variable
+## location.
+
+# CHECK: ![[VARB:.*]] = !DILocalVariable(name: "b"
+# CHECK: ![[VARC:.*]] = !DILocalVariable(name: "c"
+# CHECK: $at = COPY $a2
+# CHECK-NEXT: DBG_VALUE $at, $noreg, ![[VARC]], !DIExpression(), debug-location
+# CHECK: $s0 = COPY $a1
+# CHECK-NEXT: DBG_VALUE $s0, $noreg, ![[VARB]], !DIExpression(), debug-location
+
+--- |
+  ; ModuleID = 'test.c'
+  source_filename = "test.c"
+  target datalayout = "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"
+  target triple = "mips-unknown-linux-gnu"
+
+  ; Function Attrs: nounwind
+  define dso_local i32 @fn2(i32 signext %a, i32 signext %b, i32 signext %c) local_unnamed_addr !dbg !7 {
+  entry:
+    call void @llvm.dbg.value(metadata i32 %a, metadata !12, metadata !DIExpression()), !dbg !16
+    call void @llvm.dbg.value(metadata i32 %b, metadata !13, metadata !DIExpression()), !dbg !16
+    call void @llvm.dbg.value(metadata i32 %c, metadata !14, metadata !DIExpression()), !dbg !16
+    %add = add nsw i32 %b, %a, !dbg !17
+    %add1 = add nsw i32 %b, 10, !dbg !18
+    %call = tail call i32 @fn1(i32 signext %add, i32 signext %c, i32 signext %add1), !dbg !19
+    call void @llvm.dbg.value(metadata i32 %call, metadata !15, metadata !DIExpression()), !dbg !16
+    %cmp = icmp sgt i32 %call, 10, !dbg !20
+    %add2 = add nsw i32 %call, 10, !dbg !22
+    %retval.0 = select i1 %cmp, i32 %add2, i32 %b, !dbg !22
+    ret i32 %retval.0, !dbg !23
+  }
+
+  declare !dbg !24 dso_local i32 @fn1(i32 signext, i32 signext, i32 signext) local_unnamed_addr
+
+  ; Function Attrs: nofree nosync nounwind readnone speculatable willreturn mustprogress
+  declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!3, !4, !5}
+  !llvm.ident = !{!6}
+
+  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+  !1 = !DIFile(filename: "test.c", directory: "/dir")
+  !2 = !{}
+  !3 = !{i32 7, !"Dwarf Version", i32 4}
+  !4 = !{i32 2, !"Debug Info Version", i32 3}
+  !5 = !{i32 1, !"wchar_size", i32 4}
+  !6 = !{!"clang version 13.0.0"}
+  !7 = distinct !DISubprogram(name: "fn2", scope: !1, file: !1, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !11)
+  !8 = !DISubroutineType(types: !9)
+  !9 = !{!10, !10, !10, !10}
+  !10 = !DIBasicType(name: "long int", size: 32, encoding: DW_ATE_signed)
+  !11 = !{!12, !13, !14, !15}
+  !12 = !DILocalVariable(name: "a", arg: 1, scope: !7, file: !1, line: 2, type: !10)
+  !13 = !DILocalVariable(name: "b", arg: 2, scope: !7, file: !1, line: 2, type: !10)
+  !14 = !DILocalVariable(name: "c", arg: 3, scope: !7, file: !1, line: 2, type: !10)
+  !15 = !DILocalVariable(name: "local", scope: !7, file: !1, line: 3, type: !10)
+  !16 = !DILocation(line: 0, scope: !7)
+  !17 = !DILocation(line: 3, column: 22, scope: !7)
+  !18 = !DILocation(line: 3, column: 30, scope: !7)
+  !19 = !DILocation(line: 3, column: 17, scope: !7)
+  !20 = !DILocation(line: 4, column: 14, scope: !21)
+  !21 = distinct !DILexicalBlock(scope: !7, file: !1, line: 4, column: 8)
+  !22 = !DILocation(line: 4, column: 8, scope: !7)
+  !23 = !DILocation(line: 7, column: 2, scope: !7)
+  !24 = !DISubprogram(name: "fn1", scope: !1, file: !1, line: 1, type: !8, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
+
+...
+---
+name:            fn2
+alignment:       4
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: gpr32, preferred-register: '' }
+  - { id: 1, class: gpr32, preferred-register: '' }
+  - { id: 2, class: gpr32, preferred-register: '' }
+  - { id: 3, class: gpr32, preferred-register: '' }
+  - { id: 4, class: gpr32, preferred-register: '' }
+  - { id: 5, class: gpr32, preferred-register: '' }
+  - { id: 6, class: gpr32, preferred-register: '' }
+  - { id: 7, class: gpr32, preferred-register: '' }
+  - { id: 8, class: gpr32, preferred-register: '' }
+liveins:
+  - { reg: '$a0', virtual-reg: '%0' }
+  - { reg: '$a1', virtual-reg: '%1' }
+  - { reg: '$a2', virtual-reg: '%2' }
+body:             |
+  bb.0.entry:
+    liveins: $a0, $a1, $a2
+  
+    DBG_VALUE $a0, $noreg, !12, !DIExpression(), debug-location !16
+    DBG_VALUE $a1, $noreg, !13, !DIExpression(), debug-location !16
+    DBG_VALUE $a2, $noreg, !14, !DIExpression(), debug-location !16
+    %2:gpr32 = COPY $a2
+    DBG_VALUE %2, $noreg, !14, !DIExpression(), debug-location !16
+    %8:gpr32 = COPY $a1
+    DBG_VALUE %8, $noreg, !13, !DIExpression(), debug-location !16
+    %0:gpr32 = COPY $a0
+    DBG_VALUE %0, $noreg, !12, !DIExpression(), debug-location !16
+    %3:gpr32 = nsw ADDu %8, %0, debug-location !17
+    ADJCALLSTACKDOWN 16, 0, implicit-def dead $sp, implicit $sp, debug-location !19
+    %4:gpr32 = nsw ADDiu %8, 10, debug-location !18
+    $a0 = COPY %3, debug-location !19
+    $a1 = COPY %2, debug-location !19
+    DBG_VALUE $a1, $noreg, !14, !DIExpression(), debug-location !16
+    $a2 = COPY %4, debug-location !19
+    JAL @fn1, csr_o32, implicit-def dead $ra, implicit $a0, implicit $a1, implicit $a2, implicit-def $sp, implicit-def $v0, debug-location !19
+    ADJCALLSTACKUP 16, 0, implicit-def dead $sp, implicit $sp, debug-location !19
+    %5:gpr32 = COPY killed $v0, debug-location !19
+    DBG_VALUE %5, $noreg, !15, !DIExpression(), debug-location !16
+    %6:gpr32 = SLTi %5, 11, debug-location !22
+    %7:gpr32 = nsw ADDiu %5, 10, debug-location !22
+    %8:gpr32 = MOVZ_I_I %7, %6, %8, debug-location !22
+    $v0 = COPY %8, debug-location !23
+    RetRA implicit killed $v0, debug-location !23
+
+...

llvm/test/DebugInfo/X86/dbg-addr-dse.ll

@@ -46,8 +46,8 @@ entry:
 }
 
 ; ASM-LABEL: f: # @f
-; ASM: movl    %ecx, [[OFF_X:[0-9]+]](%rsp)
-; ASM: #DEBUG_VALUE: f:x <- [DW_OP_plus_uconst [[OFF_X]]] [$rsp+0]
+; ASM: #DEBUG_VALUE: f:x <- [DW_OP_plus_uconst [[OFF_X:[0-9]+]]] [$rsp+0]
+; ASM: movl    %ecx, [[OFF_X]](%rsp)
 ; ASM: callq   escape
 ; ASM: #DEBUG_VALUE: f:x <- 1
 ; ASM: movl    $1, global(%rip)