[LoopVectorize] Keep hints from original loop on the vector loop
We need to keep loop hints from the original loop on the new vector loop.
Failure to do this meant that, for example:
void foo(int *b) {
#pragma clang loop unroll(disable)
for (int i = 0; i < 16; ++i)
b[i] = 1;
}
this loop would be unrolled. Why? Because we'd vectorize it, thus dropping the
hints that unrolling should be disabled, and then we'd unroll it.
llvm-svn: 267970
diff --git a/llvm/test/Transforms/LoopVectorize/hints-trans.ll b/llvm/test/Transforms/LoopVectorize/hints-trans.ll
new file mode 100644
index 0000000..ec5ddbb
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/hints-trans.ll
@@ -0,0 +1,30 @@
+; RUN: opt -S -loop-vectorize -force-vector-interleave=1 -force-vector-width=4 -instsimplify -simplifycfg < %s | FileCheck %s
+; Note: -instsimplify -simplifycfg remove the (now dead) original loop, making
+; it easy to test that the llvm.loop.unroll.disable hint is still present.
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: norecurse nounwind uwtable
+define void @foo(i32* nocapture %b) #0 {
+entry:
+ br label %for.body
+
+for.cond.cleanup: ; preds = %for.body
+ ret void
+
+for.body: ; preds = %for.body, %entry
+ %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %b, i64 %indvars.iv
+ store i32 1, i32* %arrayidx, align 4
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %exitcond = icmp eq i64 %indvars.iv.next, 16
+ br i1 %exitcond, label %for.cond.cleanup, label %for.body, !llvm.loop !0
+}
+
+; CHECK-LABEL: @foo
+; CHECK: = !{!"llvm.loop.unroll.disable"}
+
+attributes #0 = { norecurse nounwind uwtable }
+
+!0 = distinct !{!0, !1}
+!1 = !{!"llvm.loop.unroll.disable"}