Do not add unroll disable metadata after unrolling pass for loops with #pragma clang...

llvm-svn: 213789

diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index ff2b8ed..2e94a44 100644 (file)
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -457,9 +457,10 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
   }
 
   if (HasPragma) {
-    // Mark loop as unrolled to prevent unrolling beyond that
-    // requested by the pragma.
-    SetLoopAlreadyUnrolled(L);
+    if (PragmaCount != 0)
+      // If loop has an unroll count pragma mark loop as unrolled to prevent
+      // unrolling beyond that requested by the pragma.
+      SetLoopAlreadyUnrolled(L);
 
     // Emit optimization remarks if we are unable to unroll the loop
     // as directed by a pragma.

diff --git a/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll b/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
index dcde9eb..04f8f48 100644 (file)
--- a/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
+++ b/llvm/test/Transforms/LoopUnroll/unroll-pragmas-disabled.ll
@@ -1,14 +1,14 @@
 ; RUN: opt < %s -loop-unroll -S | FileCheck %s
 ;
-; Verify that the unrolling pass removes existing loop unrolling metadata
+; Verify that the unrolling pass removes existing unroll count metadata
 ; and adds a disable unrolling node after unrolling is complete.
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-; #pragma clang loop  vectorize(enable) unroll(full) unroll_count(4) vectorize_width(8)
+; #pragma clang loop  vectorize(enable) unroll_count(4) vectorize_width(8)
 ;
-; Unroll metadata should be replaced with unroll(disable).  Vectorize
+; Unroll count metadata should be replaced with unroll(disable).  Vectorize
 ; metadata should be untouched.
 ;
 ; CHECK-LABEL: @loop1(
@@ -30,19 +30,49 @@ for.body:                                         ; preds = %for.body, %entry
 for.end:                                          ; preds = %for.body
   ret void
 }
-!1 = metadata !{metadata !1, metadata !2, metadata !3, metadata !4, metadata !5}
+!1 = metadata !{metadata !1, metadata !2, metadata !3, metadata !4}
 !2 = metadata !{metadata !"llvm.loop.vectorize.enable", i1 true}
-!3 = metadata !{metadata !"llvm.loop.unroll.full"}
-!4 = metadata !{metadata !"llvm.loop.unroll.count", i32 4}
-!5 = metadata !{metadata !"llvm.loop.vectorize.width", i32 8}
+!3 = metadata !{metadata !"llvm.loop.unroll.count", i32 4}
+!4 = metadata !{metadata !"llvm.loop.vectorize.width", i32 8}
 
-; #pragma clang loop unroll(disable)
+; #pragma clang loop unroll(full)
 ;
-; Unroll metadata should not change.
+; An unroll disable metadata node is only added for the unroll count case.
+; In this case, the loop has a full unroll metadata but can't be fully unrolled
+; because the trip count is dynamic.  The full unroll metadata should remain
+; after unrolling.
 ;
 ; CHECK-LABEL: @loop2(
 ; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_2:.*]]
-define void @loop2(i32* nocapture %a) {
+define void @loop2(i32* nocapture %a, i32 %b) {
+entry:
+  %cmp3 = icmp sgt i32 %b, 0
+  br i1 %cmp3, label %for.body, label %for.end, !llvm.loop !5
+
+for.body:                                         ; preds = %entry, %for.body
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32* %a, i64 %indvars.iv
+  %0 = load i32* %arrayidx, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, i32* %arrayidx, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %b
+  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !5
+
+for.end:                                          ; preds = %for.body, %entry
+  ret void
+}
+!5 = metadata !{metadata !5, metadata !6}
+!6 = metadata !{metadata !"llvm.loop.unroll.full"}
+
+; #pragma clang loop unroll(disable)
+;
+; Unroll metadata should not change.
+;
+; CHECK-LABEL: @loop3(
+; CHECK: br i1 {{.*}}, label {{.*}}, label {{.*}}, !llvm.loop ![[LOOP_3:.*]]
+define void @loop3(i32* nocapture %a) {
 entry:
   br label %for.body
 
@@ -54,16 +84,18 @@ for.body:                                         ; preds = %for.body, %entry
   store i32 %inc, i32* %arrayidx, align 4
   %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
   %exitcond = icmp eq i64 %indvars.iv.next, 64
-  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !6
+  br i1 %exitcond, label %for.end, label %for.body, !llvm.loop !7
 
 for.end:                                          ; preds = %for.body
   ret void
 }
-!6 = metadata !{metadata !6, metadata !7}
-!7 = metadata !{metadata !"llvm.loop.unroll.disable"}
+!7 = metadata !{metadata !7, metadata !8}
+!8 = metadata !{metadata !"llvm.loop.unroll.disable"}
 
 ; 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}
 ; CHECK: ![[UNROLL_DISABLE]] = metadata !{metadata !"llvm.loop.unroll.disable"}
-; CHECK: ![[LOOP_2]] = metadata !{metadata ![[LOOP_2]], metadata ![[UNROLL_DISABLE:.*]]}
+; 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:.*]]}