[LoopVectorize] Propagate known metadata to vectorized instructions

There are some kinds of metadata that are safe to propagate from the scalar
instructions to the vector instructions (fpmath and tbaa currently).

Regarding TBAA, one might worry about propagating it on if-converted loads and
stores, because the metadata might have had a control dependency on the
condition, and thus actually aliased with some other non-speculated memory
access when the condition was false. However, this would be caught by the
runtime overlap checks.

llvm-svn: 213452

1 files changed, 44 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/metadata.ll b/llvm/test/Transforms/LoopVectorize/metadata.ll
new file mode 100644
index 00000000000..bdcf1c9fb22
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/metadata.ll
@@ -0,0 +1,44 @@
+; RUN: opt < %s  -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind uwtable
+define i32 @test1(i32* nocapture %a, float* nocapture readonly %b) #0 {
+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* %b, i64 %indvars.iv
+  %0 = load float* %arrayidx, align 4, !tbaa !0
+  %conv = fptosi float %0 to i32
+  %arrayidx2 = getelementptr inbounds i32* %a, i64 %indvars.iv
+  store i32 %conv, i32* %arrayidx2, align 4, !tbaa !4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 1600
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret i32 0
+}
+
+; CHECK-LABEL: @test1
+; CHECK: load <4 x float>* %{{.*}}, align 4, !tbaa ![[TFLT:[0-9]+]]
+; CHECK: store <4 x i32> %{{.*}}, <4 x i32>* %{{.*}}, align 4, !tbaa ![[TINT:[0-9]+]]
+; CHECK: ret i32 0
+
+; CHECK-DAG: ![[TFLT]] = metadata !{metadata ![[TFLT1:[0-9]+]]
+; CHECK-DAG: ![[TFLT1]] = metadata !{metadata !"float"
+
+; CHECK-DAG: ![[TINT]] = metadata !{metadata ![[TINT1:[0-9]+]]
+; CHECK-DAG: ![[TINT1]] = metadata !{metadata !"int"
+
+attributes #0 = { nounwind uwtable }
+
+!0 = metadata !{metadata !1, metadata !1, i64 0}
+!1 = metadata !{metadata !"float", metadata !2, i64 0}
+!2 = metadata !{metadata !"omnipotent char", metadata !3, i64 0}
+!3 = metadata !{metadata !"Simple C/C++ TBAA"}
+!4 = metadata !{metadata !5, metadata !5, i64 0}
+!5 = metadata !{metadata !"int", metadata !2, i64 0}
+