Mark vector loops as already vectorized

Make sure we mark all loops (scalar and vector) when vectorizing,
so that we don't try to vectorize them anymore. Also, set unroll
to 1, since this is what we check for on early exit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193349 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 72ddb749d6333461739acea282a2525906f3a4fd..317c1ffd85c50978fd5665734deb92fd4da1a172 100644 (file)
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -801,6 +801,7 @@ struct LoopVectorizeHints {
         Vals.push_back(LoopID->getOperand(i));
 
     Vals.push_back(createHint(Context, Twine(Prefix(), "width").str(), Width));
+    Vals.push_back(createHint(Context, Twine(Prefix(), "unroll").str(), 1));
 
     MDNode *NewLoopID = MDNode::get(Context, Vals);
     // Set operand 0 to refer to the loop id itself.
@@ -1785,6 +1786,9 @@ InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
   LoopExitBlock = ExitBlock;
   LoopVectorBody = VecBody;
   LoopScalarBody = OldBasicBlock;
+
+  LoopVectorizeHints Hints(Lp, true);
+  Hints.setAlreadyVectorized(Lp);
 }
 
 /// This function returns the identity element (or neutral element) for

diff --git a/test/Transforms/LoopVectorize/already-vectorized.ll b/test/Transforms/LoopVectorize/already-vectorized.ll
new file mode 100644 (file)
index 0000000..885418c
--- /dev/null
+++ b/test/Transforms/LoopVectorize/already-vectorized.ll
@@ -0,0 +1,46 @@
+; RUN: opt < %s -debug-only=loop-vectorize -O3 -S 2>&1 | FileCheck %s
+; REQUIRES: asserts
+; We want to make sure that we don't even try to vectorize loops again
+; The vectorizer used to mark the un-vectorized loop only as already vectorized
+; thus, trying to vectorize the vectorized loop again
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@a = external global [255 x i32]
+
+; Function Attrs: nounwind readonly uwtable
+define i32 @vect() {
+; CHECK: LV: Checking a loop in "vect"
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+; We need to make sure we did vectorize the loop
+; CHECK: LV: Found a loop: for.body
+; CHECK: LV: We can vectorize this loop!
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %red.05 = phi i32 [ 0, %entry ], [ %add, %for.body ]
+  %arrayidx = getelementptr inbounds [255 x i32]* @a, i64 0, i64 %indvars.iv
+  %0 = load i32* %arrayidx, align 4
+  %add = add nsw i32 %0, %red.05
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 255
+  br i1 %exitcond, label %for.end, label %for.body
+
+; If it did, we have two loops:
+; CHECK: vector.body:
+; CHECK: br {{.*}} label %vector.body, !llvm.loop [[vect:![0-9]+]]
+; CHECK: for.body:
+; CHECK: br {{.*}} label %for.body, !llvm.loop [[scalar:![0-9]+]]
+
+for.end:                                          ; preds = %for.body
+  ret i32 %add
+}
+
+; Now, we check for the Hint metadata
+; CHECK: [[vect]] = metadata !{metadata [[vect]], metadata [[width:![0-9]+]], metadata [[unroll:![0-9]+]]}
+; CHECK: [[width]] = metadata !{metadata !"llvm.vectorizer.width", i32 1}
+; CHECK: [[unroll]] = metadata !{metadata !"llvm.vectorizer.unroll", i32 1}
+; CHECK: [[scalar]] = metadata !{metadata [[scalar]], metadata [[width]], metadata [[unroll]]}
+

diff --git a/test/Transforms/LoopVectorize/vectorize-once.ll b/test/Transforms/LoopVectorize/vectorize-once.ll
index 062c51680f6666a40ef045b53bdfdbcc9c2b10ba..780046930e1bbdaa688bc33b11390bfa69840ab2 100644 (file)
--- a/test/Transforms/LoopVectorize/vectorize-once.ll
+++ b/test/Transforms/LoopVectorize/vectorize-once.ll
@@ -68,9 +68,10 @@ _ZSt10accumulateIPiiET0_T_S2_S1_.exit:            ; preds = %for.body.i, %entry
 
 attributes #0 = { nounwind readonly ssp uwtable "fp-contract-model"="standard" "no-frame-pointer-elim" "no-frame-pointer-elim-non-leaf" "realign-stack" "relocation-model"="pic" "ssp-buffers-size"="8" }
 
-; CHECK: !0 = metadata !{metadata !0, metadata !1}
+; CHECK: !0 = metadata !{metadata !0, metadata !1, metadata !2}
 ; CHECK: !1 = metadata !{metadata !"llvm.vectorizer.width", i32 1}
-; CHECK: !2 = metadata !{metadata !2, metadata !1}
+; CHECK: !2 = metadata !{metadata !"llvm.vectorizer.unroll", i32 1}
+; CHECK: !3 = metadata !{metadata !3, metadata !1, metadata !2}
 
 !0 = metadata !{metadata !0, metadata !1}
 !1 = metadata !{metadata !"llvm.vectorizer.width", i32 1}