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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213900 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopUnrollPass.cpp b/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 2e94a44cad7282b325589f679403b23b3dc9eeed..3f12209e144f034870f332cb55d44230cac61a34 100644 (file)
--- a/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -302,7 +302,6 @@ static void SetLoopAlreadyUnrolled(Loop *L) {
   // Set operand 0 to refer to the loop id itself.
   NewLoopID->replaceOperandWith(0, NewLoopID);
   L->setLoopID(NewLoopID);
-  LoopID->replaceAllUsesWith(NewLoopID);
 }
 
 unsigned LoopUnroll::selectUnrollCount(

diff --git a/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll b/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
index 04f8f483af043c6e077a51b675ce21741b065087..db18f25c73ec748d95aa441225b4e38a02366192 100644 (file)
--- a/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
+++ b/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:.*]]}