[llvm] r279748 - [UNROLL] Postpone ScalarEvolution::forgetLoop after TripCountSC is expanded
Wei Mi via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 25 09:17:19 PDT 2016
Author: wmi
Date: Thu Aug 25 11:17:18 2016
New Revision: 279748
URL: http://llvm.org/viewvc/llvm-project?rev=279748&view=rev
Log:
[UNROLL] Postpone ScalarEvolution::forgetLoop after TripCountSC is expanded
when unroll runtime iteration loop.
In llvm::UnrollRuntimeLoopRemainder, if the loop to be unrolled is the inner
loop inside a loop nest, the scalar evolution needs to be dropped for its
parent loop which is done by ScalarEvolution::forgetLoop. However, we can
postpone forgetLoop to the end of UnrollRuntimeLoopRemainder so TripCountSC
expansion can still reuse existing value.
Differential Revision: https://reviews.llvm.org/D23572
Added:
llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-unroll.ll
llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll
Removed:
llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-existing-value.ll
Modified:
llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
Modified: llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp?rev=279748&r1=279747&r2=279748&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopUnrollRuntime.cpp Thu Aug 25 11:17:18 2016
@@ -491,11 +491,6 @@ bool llvm::UnrollRuntimeLoopRemainder(Lo
if (Log2_32(Count) > BEWidth)
return false;
- // If this loop is nested, then the loop unroller changes the code in the
- // parent loop, so the Scalar Evolution pass needs to be run again.
- if (Loop *ParentLoop = L->getParentLoop())
- SE->forgetLoop(ParentLoop);
-
BasicBlock *Latch = L->getLoopLatch();
// Loop structure is the following:
@@ -685,6 +680,12 @@ bool llvm::UnrollRuntimeLoopRemainder(Lo
ConnectProlog(L, BECount, Count, PrologExit, PreHeader, NewPreHeader,
VMap, DT, LI, PreserveLCSSA);
}
+
+ // If this loop is nested, then the loop unroller changes the code in the
+ // parent loop, so the Scalar Evolution pass needs to be run again.
+ if (Loop *ParentLoop = L->getParentLoop())
+ SE->forgetLoop(ParentLoop);
+
NumRuntimeUnrolled++;
return true;
}
Removed: llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-existing-value.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-existing-value.ll?rev=279747&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-existing-value.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-existing-value.ll (removed)
@@ -1,38 +0,0 @@
-; RUN: opt < %s -loop-vectorize -force-vector-width=4 -verify-scev-maps -S |FileCheck %s
-
-; SCEV expansion uses existing value when the SCEV has no AddRec expr.
-; CHECK: select
-; CHECK-NOT: select
-
- at a = common global [1000 x i16] zeroinitializer, align 16
-
-define i32 @foo(i32 %x, i32 %y) {
-entry:
- %cmp = icmp slt i32 %x, %y
- %cond = select i1 %cmp, i32 %x, i32 %y
- %cmp1.10 = icmp sgt i32 %cond, 0
- br i1 %cmp1.10, label %for.body.lr.ph, label %for.end
-
-for.body.lr.ph: ; preds = %entry
- %tmp = sext i32 %cond to i64
- br label %for.body
-
-for.body: ; preds = %for.body, %for.body.lr.ph
- %indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
- %total.011 = phi i32 [ 0, %for.body.lr.ph ], [ %add, %for.body ]
- %arrayidx = getelementptr inbounds [1000 x i16], [1000 x i16]* @a, i64 0, i64 %indvars.iv
- %tmp1 = load i16, i16* %arrayidx, align 2
- %conv = sext i16 %tmp1 to i32
- %add = add nsw i32 %conv, %total.011
- %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
- %cmp1 = icmp slt i64 %indvars.iv.next, %tmp
- br i1 %cmp1, label %for.body, label %for.end.loopexit
-
-for.end.loopexit: ; preds = %for.body
- %add.lcssa = phi i32 [ %add, %for.body ]
- br label %for.end
-
-for.end: ; preds = %for.end.loopexit, %entry
- %total.0.lcssa = phi i32 [ 0, %entry ], [ %add.lcssa, %for.end.loopexit ]
- ret i32 %total.0.lcssa
-}
Added: llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-unroll.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-unroll.ll?rev=279748&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-unroll.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-unroll.ll Thu Aug 25 11:17:18 2016
@@ -0,0 +1,35 @@
+; RUN: opt < %s -loop-unroll -unroll-runtime -unroll-count=2 -verify-scev-maps -S | FileCheck %s
+
+; Check SCEV expansion uses existing value when unrolling an inner loop with runtime trip count in a loop nest.
+; CHECK-LABEL: @foo(
+; CHECK: select
+; CHECK-NOT: select
+; CHECK: ret
+
+define void @foo(i32 %xfL, i32 %scaleL) local_unnamed_addr {
+entry:
+ br label %for.body
+
+for.body: ; preds = %for.body5, %for.body, %entry
+ %xfL.addr.033 = phi i32 [ %xfL, %entry ], [ %add, %for.body5 ]
+ %add = add nsw i32 %xfL.addr.033, %scaleL
+ %shr = ashr i32 %add, 16
+ %cmp.i = icmp slt i32 0, %shr
+ %.sroa.speculated = select i1 %cmp.i, i32 0, i32 %shr
+ %cmp425 = icmp slt i32 0, %.sroa.speculated
+ br i1 %cmp425, label %for.body5.preheader, label %for.end
+
+for.body5.preheader: ; preds = %for.body
+ %tmp0 = sext i32 %.sroa.speculated to i64
+ br label %for.body5
+
+for.body5: ; preds = %for.body5, %for.body5.preheader
+ %indvars.iv = phi i64 [ 0, %for.body5.preheader ], [ %indvars.iv.next, %for.body5 ]
+ %indvars.iv.next = add nsw i64 %indvars.iv, 1
+ %cmp4 = icmp slt i64 %indvars.iv.next, %tmp0
+ br i1 %cmp4, label %for.body5, label %for.body
+
+for.end:
+ ret void
+}
+
Added: llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll?rev=279748&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll (added)
+++ llvm/trunk/test/Analysis/ScalarEvolution/scev-expander-reuse-vect.ll Thu Aug 25 11:17:18 2016
@@ -0,0 +1,40 @@
+; RUN: opt < %s -loop-vectorize -force-vector-width=4 -verify-scev-maps -S |FileCheck %s
+
+; SCEV expansion uses existing value when the SCEV has no AddRec expr.
+; CHECK-LABEL: @foo(
+; CHECK: select
+; CHECK-NOT: select
+; CHECK: ret
+
+ at a = common global [1000 x i16] zeroinitializer, align 16
+
+define i32 @foo(i32 %x, i32 %y) {
+entry:
+ %cmp = icmp slt i32 %x, %y
+ %cond = select i1 %cmp, i32 %x, i32 %y
+ %cmp1.10 = icmp sgt i32 %cond, 0
+ br i1 %cmp1.10, label %for.body.lr.ph, label %for.end
+
+for.body.lr.ph: ; preds = %entry
+ %tmp = sext i32 %cond to i64
+ br label %for.body
+
+for.body: ; preds = %for.body, %for.body.lr.ph
+ %indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.body ]
+ %total.011 = phi i32 [ 0, %for.body.lr.ph ], [ %add, %for.body ]
+ %arrayidx = getelementptr inbounds [1000 x i16], [1000 x i16]* @a, i64 0, i64 %indvars.iv
+ %tmp1 = load i16, i16* %arrayidx, align 2
+ %conv = sext i16 %tmp1 to i32
+ %add = add nsw i32 %conv, %total.011
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+ %cmp1 = icmp slt i64 %indvars.iv.next, %tmp
+ br i1 %cmp1, label %for.body, label %for.end.loopexit
+
+for.end.loopexit: ; preds = %for.body
+ %add.lcssa = phi i32 [ %add, %for.body ]
+ br label %for.end
+
+for.end: ; preds = %for.end.loopexit, %entry
+ %total.0.lcssa = phi i32 [ 0, %entry ], [ %add.lcssa, %for.end.loopexit ]
+ ret i32 %total.0.lcssa
+}
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