[DebugInfo] Inline for without DebugLocation

[gramanas]

Summary

This test is a strip down version of a function inside the
amalgamated sqlite source. When converted to IR clang produces
a phi instruction without debug location.

It is a continuation of D47097 focusing on a different problem
of similar structure.

This was found while investigating instructions with missing DebugLoc
after running SROA on the amalgamated sqlite source, in an attempt to
try and preserve as much debug information as possible during the
early stage passes.

[aprantl]

test/CodeGen/debug-info-inline-for.c

3

Please add a comment explaining what is being tested here.

[gramanas]

Add comment explaining the test

[aprantl]

test/CodeGen/debug-info-inline-for.c

13

Shouldn't you also check *which* location is attached to it?

[gramanas]

Add artificial debug location to the phi instruction

test/CodeGen/debug-info-inline-for.c

13

I wasn't sure if this should be an artificial location or not so I left it like that for the time being. It's been updated to reflect the latest changes now.

[vsk]

As is the case with D47097, this helps preserve more scope information after SROA. LGTM. Thanks!

[gramanas]

make code more readable

[gramanas]

ping! should I commit this?

[probinson]

In D47720#1136585, @gramanas wrote:

ping! should I commit this?

@vsk accepted it, so yes go ahead.

test/CodeGen/debug-info-inline-for.c

+// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - %s | FileCheck %s
+// Check that clang emits Debug location in the phi instruction
+
+int func(int n) {
+  int a;
+  for(a = 10; a>0 && n++; a--);
+  return n;
+}
+
+// CHECK: land.end:
+// CHECK-NEXT: {{.*}} = phi i1 {{.*}} !dbg ![[DbgLoc:[0-9]+]]
+
+// CHECK: ![[DbgLoc]] = !DILocation(