[DebugInfo][LoopVectorize] Preserve DL in generated phi instruction

When creating `phi` instructions to resume at the scalar part of the loop,
copy the DebugLoc from the original phi over to the new one.

Differential Revision: https://reviews.llvm.org/D48769

llvm-svn: 336256

1 files changed, 38 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/preserve-dbg-loc-and-loop-metadata.ll b/llvm/test/Transforms/LoopVectorize/preserve-dbg-loc-and-loop-metadata.ll
new file mode 100644
index 00000000000..8880d99290d
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/preserve-dbg-loc-and-loop-metadata.ll
@@ -0,0 +1,38 @@
+; RUN: opt < %s -loop-vectorize -S 2>&1 | FileCheck %s
+; RUN: opt < %s -debugify -loop-vectorize -S | FileCheck %s -check-prefix DEBUGLOC
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; This test makes sure we don't duplicate the loop vectorizer's metadata
+; while marking them as already vectorized (by setting width = 1), even
+; at lower optimization levels, where no extra cleanup is done
+
+; DEBUGLOC-LABEL: define void @_Z3fooPf(
+; Check that the phi to resume the scalar part of the loop
+; has Debug Location.
+define void @_Z3fooPf(float* %a) {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds float, float* %a, i64 %indvars.iv
+  %p = load float, float* %arrayidx, align 4
+  %mul = fmul float %p, 2.000000e+00
+  store float %mul, float* %arrayidx, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1024
+  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !0
+
+; DEBUGLOC: scalar.ph:
+; DEBUGLOC-NEXT:    %bc.resume.val = phi {{.*}} !dbg ![[DbgLoc:[0-9]+]]
+;
+; DEBUGLOC: ![[DbgLoc]] = !DILocation(line: 2
+
+for.end:                                          ; preds = %for.body
+  ret void
+}
+
+!0 = !{!0, !1}
+!1 = !{!"llvm.loop.vectorize.width", i32 4}
+; CHECK-NOT: !{metadata !"llvm.loop.vectorize.width", i32 4}
+; CHECK: !{!"llvm.loop.isvectorized", i32 1}