[RemoveDIs] Replicate dbg intrinsic movement pattern in SelectOptimize

llvm/lib/CodeGen/SelectOptimize.cpp

@@ -621,6 +621,12 @@ void SelectOptimizeImpl::convertProfitableSIGroups(SelectGroups &ProfSIGroups) {
     SelectLike LastSI = ASI.back();
     BasicBlock *StartBlock = SI.getI()->getParent();
     BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(LastSI.getI()));
+    // With RemoveDIs turned off, SplitPt can be a dbg.* intrinsic. With
+    // RemoveDIs turned on, SplitPt would instead point to the next
+    // instruction. To match existing dbg.* intrinsic behaviour with RemoveDIs,
+    // tell splitBasicBlock that we want to include any DPValues attached to
+    // SplitPt in the splice.
+    SplitPt.setHeadBit(true);
     BasicBlock *EndBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
     BFI->setBlockFreq(EndBlock, BFI->getBlockFreq(StartBlock));
     // Delete the unconditional branch that was just created by the split.

llvm/test/DebugInfo/AArch64/select-optimize-trailing-dbg-records.ll

@@ -0,0 +1,63 @@
+; RUN: opt %s -passes='require<profile-summary>,function(select-optimize)' -o - -S \
+; RUN: | FileCheck %s
+; RUN: opt %s --try-experimental-debuginfo-iterators -passes='require<profile-summary>,function(select-optimize)' -o - -S \
+; RUN: | FileCheck %s
+
+;; Check that the dbg.value is moved into the start of the end-block of the
+;; inserted if-block.
+
+; CHECK: select.end:
+; CHECK-NEXT: %[[PHI:.*]] = phi i32
+; CHECK-NEXT: dbg.value(metadata i32 %[[PHI]],
+
+source_filename = "test.ll"
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-fuchsia"
+
+%struct.hb_glyph_info_t = type { i32, i32, i32, %union._hb_var_int_t, %union._hb_var_int_t }
+%union._hb_var_int_t = type { i32 }
+
+define void @_Z22_hb_ot_shape_normalizePK18hb_ot_shape_plan_tP11hb_buffer_tP9hb_font_t() {
+entry:
+  br label %while.body193
+
+while.body193:                                    ; preds = %while.body193, %entry
+  %starter.0337 = phi i32 [ %spec.select322, %while.body193 ], [ 0, %entry ]
+  %idxprom207 = zext i32 %starter.0337 to i64
+  %arrayidx208 = getelementptr %struct.hb_glyph_info_t, ptr null, i64 %idxprom207
+  %0 = load i32, ptr %arrayidx208, align 4
+  %call247.val = load i16, ptr null, align 4
+  %cmp249327 = icmp ult i16 %call247.val, 0
+  %cmp249 = select i1 false, i1 false, i1 %cmp249327
+  %spec.select322 = select i1 %cmp249, i32 0, i32 %starter.0337
+  tail call void @llvm.dbg.value(metadata i32 %spec.select322, metadata !13, metadata !DIExpression()), !dbg !20
+  br label %while.body193
+}
+
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!12}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !3, imports: !2, splitDebugInlining: false, nameTableKind: GNU)
+!1 = !DIFile(filename: "../../third_party/harfbuzz-ng/src/src/hb-ot-shape-normalize.cc", directory: ".")
+!2 = !{}
+!3 = !{!4, !9}
+!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
+!5 = distinct !DIGlobalVariable(scope: null, file: !1, line: 383, type: !6, isLocal: true, isDefinition: true)
+!6 = !DICompositeType(tag: DW_TAG_array_type, baseType: !7, size: 112, elements: !2)
+!7 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8)
+!8 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_unsigned_char)
+!9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression())
+!10 = distinct !DIGlobalVariable(scope: null, file: !1, line: 410, type: !11, isLocal: true, isDefinition: true)
+!11 = !DICompositeType(tag: DW_TAG_array_type, baseType: !7, size: 96, elements: !2)
+!12 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !DILocalVariable(name: "starter", scope: !14, file: !1, line: 441, type: !19)
+!14 = distinct !DILexicalBlock(scope: !15, file: !1, line: 435, column: 3)
+!15 = distinct !DILexicalBlock(scope: !16, file: !1, line: 431, column: 7)
+!16 = distinct !DISubprogram(name: "_hb_ot_shape_normalize", linkageName: "_Z22_hb_ot_shape_normalizePK18hb_ot_shape_plan_tP11hb_buffer_tP9hb_font_t", scope: !1, file: !1, line: 291, type: !17, scopeLine: 294, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!17 = distinct !DISubroutineType(types: !18)
+!18 = !{null}
+!19 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!20 = !DILocation(line: 0, scope: !14)