After unrolling a loop with llvm.loop.unroll.count metadata (unroll factor

hint) the loop unroller replaces the llvm.loop.unroll.count metadata with
llvm.loop.unroll.disable metadata to prevent any subsequent unrolling
passes from unrolling more than the hint indicates.  This patch fixes
an issue where loop unrolling could be disabled for other loops as well which
share the same llvm.loop metadata.

llvm-svn: 213900

1 files changed, 54 insertions, 6 deletions

diff --git a/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll b/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
index 04f8f483af0..db18f25c73e 100644
--- a/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
+++ b/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
@@ -11,9 +11,9 @@ target triple = "x86_64-unknown-linux-gnu"
 ; Unroll count metadata should be replaced with unroll(disable).  Vectorize
 ; metadata should be untouched.
 ;
-; CHECK-LABEL: @loop1(
+; CHECK-LABEL: @unroll_count_4(
 ; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_1:.*]]
-define void @loop1(i32* nocapture %a) {
+define void @unroll_count_4(i32* nocapture %a) {
 entry:
   br label %for.body
 
@@ -42,9 +42,9 @@ for.end:                                          ; preds = %for.body
 ; because the trip count is dynamic.  The full unroll metadata should remain
 ; after unrolling.
 ;
-; CHECK-LABEL: @loop2(
+; CHECK-LABEL: @unroll_full(
 ; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_2:.*]]
-define void @loop2(i32* nocapture %a, i32 %b) {
+define void @unroll_full(i32* nocapture %a, i32 %b) {
 entry:
   %cmp3 = icmp sgt i32 %b, 0
   br i1 %cmp3, label %for.body, label %for.end, !llvm.loop !5
@@ -70,9 +70,9 @@ for.end:                                          ; preds = %for.body, %entry
 ;
 ; Unroll metadata should not change.
 ;
-; CHECK-LABEL: @loop3(
+; CHECK-LABEL: @unroll_disable(
 ; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_3:.*]]
-define void @loop3(i32* nocapture %a) {
+define void @unroll_disable(i32* nocapture %a) {
 entry:
   br label %for.body
 
@@ -92,6 +92,52 @@ for.end:                                          ; preds = %for.body
 !7 = metadata !{metadata !7, metadata !8}
 !8 = metadata !{metadata !"llvm.loop.unroll.disable"}
 
+; This function contains two loops which share the same llvm.loop metadata node
+; with an llvm.loop.unroll.count 2 hint.  Both loops should be unrolled.  This
+; verifies that adding disable metadata to a loop after unrolling doesn't affect
+; other loops which previously shared the same llvm.loop metadata.
+;
+; CHECK-LABEL: @shared_metadata(
+; CHECK: store i32
+; CHECK: store i32
+; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_4:.*]]
+; CHECK: store i32
+; CHECK: store i32
+; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_5:.*]]
+define void @shared_metadata(i32* nocapture %List) #0 {
+entry:
+  br label %for.body3
+
+for.body3:                                        ; preds = %for.body3, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body3 ]
+  %arrayidx = getelementptr inbounds i32* %List, i64 %indvars.iv
+  %0 = load i32* %arrayidx, align 4
+  %add4 = add nsw i32 %0, 10
+  store i32 %add4, i32* %arrayidx, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 4
+  br i1 %exitcond, label %for.body3.1.preheader, label %for.body3, !llvm.loop !9
+
+for.body3.1.preheader:                            ; preds = %for.body3
+  br label %for.body3.1
+
+for.body3.1:                                      ; preds = %for.body3.1.preheader, %for.body3.1
+  %indvars.iv.1 = phi i64 [ %1, %for.body3.1 ], [ 0, %for.body3.1.preheader ]
+  %1 = add nsw i64 %indvars.iv.1, 1
+  %arrayidx.1 = getelementptr inbounds i32* %List, i64 %1
+  %2 = load i32* %arrayidx.1, align 4
+  %add4.1 = add nsw i32 %2, 10
+  store i32 %add4.1, i32* %arrayidx.1, align 4
+  %exitcond.1 = icmp eq i64 %1, 4
+  br i1 %exitcond.1, label %for.inc5.1, label %for.body3.1, !llvm.loop !9
+
+for.inc5.1:                                       ; preds = %for.body3.1
+  ret void
+}
+!9 = metadata !{metadata !9, metadata !10}
+!10 = metadata !{metadata !"llvm.loop.unroll.count", i32 2}
+
+
 ; CHECK: ![[LOOP_1]] = metadata !{metadata ![[LOOP_1]], metadata ![[VEC_ENABLE:.*]], metadata ![[WIDTH_8:.*]], metadata ![[UNROLL_DISABLE:.*]]}
 ; CHECK: ![[VEC_ENABLE]] = metadata !{metadata !"llvm.loop.vectorize.enable", i1 true}
 ; CHECK: ![[WIDTH_8]] = metadata !{metadata !"llvm.loop.vectorize.width", i32 8}
@@ -99,3 +145,5 @@ for.end:                                          ; preds = %for.body
 ; CHECK: ![[LOOP_2]] = metadata !{metadata ![[LOOP_2]], metadata ![[UNROLL_FULL:.*]]}
 ; CHECK: ![[UNROLL_FULL]] = metadata !{metadata !"llvm.loop.unroll.full"}
 ; CHECK: ![[LOOP_3]] = metadata !{metadata ![[LOOP_3]], metadata ![[UNROLL_DISABLE:.*]]}
+; CHECK: ![[LOOP_4]] = metadata !{metadata ![[LOOP_4]], metadata ![[UNROLL_DISABLE:.*]]}
+; CHECK: ![[LOOP_5]] = metadata !{metadata ![[LOOP_5]], metadata ![[UNROLL_DISABLE:.*]]}