commit 9106fe1733f134f0ea5089155dc35d24d272f257
author Davide Italiano <ditaliano@apple.com> Mon Jun 15 14:25:30 2020 -0700
committer Copybara-Service <copybara-worker@google.com> Mon Oct 26 17:53:19 2020 -0700
tree c41bc60011b9bfaa4a55213d7b372c44c5421ac6
parent cb52c5f00f773bfb19b8c96cfb988455960cb027

[CodeGenPrepare] Reset the debug location when promoting trunc(s)

The promotion machinery in CGP moves instructions retaining
debug locations. When the transformation is local, this is mostly
correct, but when instructions are moved cross-BBs, this is not
always true and causes jumpiness in line tables. This is the first
of a series of commits. sext(s) and zext(s) need to be treated
similarly.

Differential Revision:  https://reviews.llvm.org/D81879

GitOrigin-RevId: c2dccf9d5e34278cb2ed0a018405848850508b99

lib/CodeGen/CodeGenPrepare.cpp

diff --git a/lib/CodeGen/CodeGenPrepare.cpp b/lib/CodeGen/CodeGenPrepare.cpp
index d238804..935fc95 100644
--- a/lib/CodeGen/CodeGenPrepare.cpp
+++ b/lib/CodeGen/CodeGenPrepare.cpp
@@ -2605,6 +2605,7 @@
     /// trunc Opnd to Ty.
     TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
       IRBuilder<> Builder(Opnd);
+      Builder.SetCurrentDebugLocation(DebugLoc());
       Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
       LLVM_DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n");
     }

test/Transforms/CodeGenPrepare/X86/promoted-trunc-loc.ll

diff --git a/test/Transforms/CodeGenPrepare/X86/promoted-trunc-loc.ll b/test/Transforms/CodeGenPrepare/X86/promoted-trunc-loc.ll
new file mode 100644
index 0000000..12b5a148
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/X86/promoted-trunc-loc.ll
@@ -0,0 +1,44 @@
+; RUN: opt < %s -codegenprepare -S -mtriple=x86_64-unknown-unknown | FileCheck %s
+
+; Make sure the promoted trunc doesn't get a debug location associated.
+; CHECK: %promoted = trunc i32 %or to i16
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.13.0"
+
+@b = global i16 0, align 2
+
+declare void @bar(i64)
+
+define i32 @foo(i16 %kkk) !dbg !6 {
+entry:
+  %t4 = load i16, i16* @b, align 2, !dbg !8
+  %conv4 = zext i16 %t4 to i32, !dbg !9
+  %or = or i16 %kkk, %t4, !dbg !10
+  %c = sext i16 %or to i64, !dbg !11
+  call void @bar(i64 %c), !dbg !12
+  %t5 = and i16 %or, 5, !dbg !13
+  %z = zext i16 %t5 to i32, !dbg !14
+  ret i32 %z, !dbg !15
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.debugify = !{!3, !4}
+!llvm.module.flags = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "/Users/davide/work/llvm-project/patatino.ll", directory: "/")
+!2 = !{}
+!3 = !{i32 8}
+!4 = !{i32 0}
+!5 = !{i32 2, !"Debug Info Version", i32 3}
+!6 = distinct !DISubprogram(name: "foo", linkageName: "foo", scope: null, file: !1, line: 1, type: !7, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
+!7 = !DISubroutineType(types: !2)
+!8 = !DILocation(line: 1, column: 1, scope: !6)
+!9 = !DILocation(line: 2, column: 1, scope: !6)
+!10 = !DILocation(line: 3, column: 1, scope: !6)
+!11 = !DILocation(line: 4, column: 1, scope: !6)
+!12 = !DILocation(line: 5, column: 1, scope: !6)
+!13 = !DILocation(line: 6, column: 1, scope: !6)
+!14 = !DILocation(line: 7, column: 1, scope: !6)
+!15 = !DILocation(line: 8, column: 1, scope: !6)