Debug Info: Fix the SDLoc propagation for a DAGCombiner rule

This patch ensures that the rule:
  fold (zext (load x)) -> (zext (truncate (zextload x)))
propagates the SDLoc of the load to the zextload.

<rdar://problem/33755881>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315340 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/X86/load-combine-dbg.ll b/test/CodeGen/X86/load-combine-dbg.ll
new file mode 100644 (file)
index 0000000..59e6e1a
--- /dev/null
+++ b/test/CodeGen/X86/load-combine-dbg.ll
@@ -0,0 +1,37 @@
+; RUN: llc -O0 < %s -mtriple=x86_64-unknown | FileCheck %s
+; This was extracted from a swift debugger stepping testcase and checks that the
+;   fold (zext (load x)) -> (zext (truncate (zextload x)))
+; rule propagates the SDLoc of the load to the zextload.
+
+; CHECK: .loc {{.*}} main.swift:100
+; CHECK-NOT: .loc
+; CHECK: .loc {{.*}} main.swift:200
+; CHECK-NOT: .loc
+; CHECK: .loc {{.*}} main.swift:300
+; CHECK-NOT: .loc
+declare void @foo(double)
+
+define i32 @zext_load(i32* %arg) !dbg !30 {
+  %1 = bitcast i32* %arg to i8*
+  %2 = getelementptr inbounds i8, i8* %1, i32 1
+  %3 = load i8, i8* %2, align 1, !dbg !100
+  %4 = uitofp i8 %3 to double, !dbg !200
+  call void @foo(double %4), !dbg !200
+  %5 = zext i8 %3 to i32, !dbg !300
+  ret i32 %5
+}
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !3, isOptimized: false, emissionKind: FullDebug)
+!2 = !DIModule(scope: null, name: "test", includePath: "", isysroot: "/")
+!3 = !DIFile(filename: "main.swift", directory: "/")
+
+!30 = distinct !DISubprogram(name: "main", scope: !2, file: !3, line: 1, type: !31, isLocal: false, isDefinition: true, isOptimized: false, unit: !1)
+!31 = !DISubroutineType(types: !32)
+!32 = !{}
+
+!100 = !DILocation(line: 100, scope: !30)
+!200 = !DILocation(line: 200, scope: !30)
+!300 = !DILocation(line: 300, scope: !30)