[llvm] cfc741b - [LoopPeel] Forget SCEV for updated exit phi values.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 20 04:19:54 PDT 2022
Author: Florian Hahn
Date: 2022-06-20T13:19:27+02:00
New Revision: cfc741bc0e029e931e9188a201de0567b00bc0fd
URL: https://github.com/llvm/llvm-project/commit/cfc741bc0e029e931e9188a201de0567b00bc0fd
DIFF: https://github.com/llvm/llvm-project/commit/cfc741bc0e029e931e9188a201de0567b00bc0fd.diff
LOG: [LoopPeel] Forget SCEV for updated exit phi values.
LoopPeel add new incoming values to exit phi nodes which can change the
SCEV for the phi after 20d798bd47ec51.
Forget SCEVs for such phis.
Fixes #56044.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D128164
Added:
Modified:
llvm/lib/Transforms/Utils/LoopPeel.cpp
llvm/test/Transforms/LoopUnroll/scevunroll.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Utils/LoopPeel.cpp b/llvm/lib/Transforms/Utils/LoopPeel.cpp
index d108fbbc26147..7f0852cef8ec9 100644
--- a/llvm/lib/Transforms/Utils/LoopPeel.cpp
+++ b/llvm/lib/Transforms/Utils/LoopPeel.cpp
@@ -577,7 +577,8 @@ static void cloneLoopBlocks(
SmallVectorImpl<std::pair<BasicBlock *, BasicBlock *>> &ExitEdges,
SmallVectorImpl<BasicBlock *> &NewBlocks, LoopBlocksDFS &LoopBlocks,
ValueToValueMapTy &VMap, ValueToValueMapTy &LVMap, DominatorTree *DT,
- LoopInfo *LI, ArrayRef<MDNode *> LoopLocalNoAliasDeclScopes) {
+ LoopInfo *LI, ArrayRef<MDNode *> LoopLocalNoAliasDeclScopes,
+ ScalarEvolution &SE) {
BasicBlock *Header = L->getHeader();
BasicBlock *Latch = L->getLoopLatch();
BasicBlock *PreHeader = L->getLoopPreheader();
@@ -683,6 +684,7 @@ static void cloneLoopBlocks(
if (LatchInst && L->contains(LatchInst))
LatchVal = VMap[LatchVal];
PHI.addIncoming(LatchVal, cast<BasicBlock>(VMap[Edge.first]));
+ SE.forgetValue(&PHI);
}
// LastValueMap is updated with the values for the current loop
@@ -849,7 +851,7 @@ bool llvm::peelLoop(Loop *L, unsigned PeelCount, LoopInfo *LI,
cloneLoopBlocks(L, Iter, InsertTop, InsertBot, ExitEdges, NewBlocks,
LoopBlocks, VMap, LVMap, &DT, LI,
- LoopLocalNoAliasDeclScopes);
+ LoopLocalNoAliasDeclScopes, *SE);
// Remap to use values from the current iteration instead of the
// previous one.
diff --git a/llvm/test/Transforms/LoopUnroll/scevunroll.ll b/llvm/test/Transforms/LoopUnroll/scevunroll.ll
index 70c8d29e4a826..80cb74557fdf1 100644
--- a/llvm/test/Transforms/LoopUnroll/scevunroll.ll
+++ b/llvm/test/Transforms/LoopUnroll/scevunroll.ll
@@ -342,3 +342,96 @@ return: ; preds = %for.body, %for.cond
store i32 %b.03.lcssa, i32* %a, align 4
ret void
}
+
+; Test case for PR56044. Check that SCEVs for exit phis are properly invalidated.
+define i32 @test_pr56044(i64* %src, i32 %a) {
+; CHECK-LABEL: @test_pr56044(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label [[LOOP_1_PEEL_BEGIN:%.*]]
+; CHECK: loop.1.peel.begin:
+; CHECK-NEXT: br label [[LOOP_1_PEEL:%.*]]
+; CHECK: loop.1.peel:
+; CHECK-NEXT: call void @fn(i32 5)
+; CHECK-NEXT: [[L_PEEL:%.*]] = load i64, i64* [[SRC:%.*]], align 8
+; CHECK-NEXT: [[ADD_PEEL:%.*]] = add i64 [[L_PEEL]], [[L_PEEL]]
+; CHECK-NEXT: [[EC_1_PEEL:%.*]] = icmp sgt i32 [[A:%.*]], 4
+; CHECK-NEXT: br i1 [[EC_1_PEEL]], label [[MID:%.*]], label [[LOOP_1_PEEL_NEXT:%.*]]
+; CHECK: loop.1.peel.next:
+; CHECK-NEXT: br label [[LOOP_1_PEEL_NEXT1:%.*]]
+; CHECK: loop.1.peel.next1:
+; CHECK-NEXT: br label [[ENTRY_PEEL_NEWPH:%.*]]
+; CHECK: entry.peel.newph:
+; CHECK-NEXT: br label [[LOOP_1:%.*]]
+; CHECK: loop.1:
+; CHECK-NEXT: call void @fn(i32 18)
+; CHECK-NEXT: [[L:%.*]] = load i64, i64* [[SRC]], align 8
+; CHECK-NEXT: [[ADD:%.*]] = add i64 [[L]], [[L]]
+; CHECK-NEXT: [[EC_1:%.*]] = icmp sgt i32 [[A]], 4
+; CHECK-NEXT: br i1 [[EC_1]], label [[MID_LOOPEXIT:%.*]], label [[LOOP_1]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK: mid.loopexit:
+; CHECK-NEXT: [[LCSSA_1_PH:%.*]] = phi i64 [ [[ADD]], [[LOOP_1]] ]
+; CHECK-NEXT: br label [[MID]]
+; CHECK: mid:
+; CHECK-NEXT: [[LCSSA_1:%.*]] = phi i64 [ [[ADD_PEEL]], [[LOOP_1_PEEL]] ], [ [[LCSSA_1_PH]], [[MID_LOOPEXIT]] ]
+; CHECK-NEXT: [[TRUNC:%.*]] = trunc i64 [[LCSSA_1]] to i32
+; CHECK-NEXT: [[ADD_2:%.*]] = sub i32 [[A]], [[TRUNC]]
+; CHECK-NEXT: br label [[LOOP_2_PEEL_BEGIN:%.*]]
+; CHECK: loop.2.peel.begin:
+; CHECK-NEXT: br label [[LOOP_2_PEEL:%.*]]
+; CHECK: loop.2.peel:
+; CHECK-NEXT: [[IV_2_NEXT_PEEL:%.*]] = add i32 0, [[ADD_2]]
+; CHECK-NEXT: [[IV_1_NEXT_PEEL:%.*]] = add nuw nsw i32 0, 1
+; CHECK-NEXT: [[EC_2_PEEL:%.*]] = icmp ult i32 [[IV_1_NEXT_PEEL]], 12345
+; CHECK-NEXT: br i1 [[EC_2_PEEL]], label [[LOOP_2_PEEL_NEXT:%.*]], label [[EXIT:%.*]]
+; CHECK: loop.2.peel.next:
+; CHECK-NEXT: br label [[LOOP_2_PEEL_NEXT2:%.*]]
+; CHECK: loop.2.peel.next2:
+; CHECK-NEXT: br label [[MID_PEEL_NEWPH:%.*]]
+; CHECK: mid.peel.newph:
+; CHECK-NEXT: br label [[LOOP_2:%.*]]
+; CHECK: loop.2:
+; CHECK-NEXT: [[IV_1:%.*]] = phi i32 [ [[IV_1_NEXT_PEEL]], [[MID_PEEL_NEWPH]] ], [ [[IV_1_NEXT:%.*]], [[LOOP_2]] ]
+; CHECK-NEXT: [[IV_2:%.*]] = phi i32 [ [[IV_2_NEXT_PEEL]], [[MID_PEEL_NEWPH]] ], [ [[IV_2_NEXT:%.*]], [[LOOP_2]] ]
+; CHECK-NEXT: [[IV_2_NEXT]] = add i32 2, [[IV_2]]
+; CHECK-NEXT: [[IV_1_NEXT]] = add nuw nsw i32 [[IV_1]], 1
+; CHECK-NEXT: [[EC_2:%.*]] = icmp ult i32 [[IV_1_NEXT]], 12345
+; CHECK-NEXT: br i1 [[EC_2]], label [[LOOP_2]], label [[EXIT_LOOPEXIT:%.*]], !llvm.loop [[LOOP2:![0-9]+]]
+; CHECK: exit.loopexit:
+; CHECK-NEXT: [[LCSSA_2_PH:%.*]] = phi i32 [ [[IV_2_NEXT]], [[LOOP_2]] ]
+; CHECK-NEXT: br label [[EXIT]]
+; CHECK: exit:
+; CHECK-NEXT: [[LCSSA_2:%.*]] = phi i32 [ [[IV_2_NEXT_PEEL]], [[LOOP_2_PEEL]] ], [ [[LCSSA_2_PH]], [[EXIT_LOOPEXIT]] ]
+; CHECK-NEXT: ret i32 [[LCSSA_2]]
+;
+entry:
+ br label %loop.1
+
+loop.1:
+ %p.1 = phi i32 [ 5, %entry ], [ 18, %loop.1 ]
+ call void @fn(i32 %p.1)
+ %l = load i64, i64* %src, align 8
+ %add = add i64 %l, %l
+ %ec.1 = icmp sgt i32 %a, 4
+ br i1 %ec.1, label %mid, label %loop.1
+
+mid:
+ %lcssa.1 = phi i64 [ %add, %loop.1 ]
+ %trunc = trunc i64 %lcssa.1 to i32
+ %add.2 = sub i32 %a, %trunc
+ br label %loop.2
+
+loop.2:
+ %iv.1 = phi i32 [ 0, %mid ], [ %iv.1.next, %loop.2 ]
+ %iv.2 = phi i32 [ %add.2, %mid ], [ %iv.2.next, %loop.2 ]
+ %p.2 = phi i32 [ 0, %mid ], [ 2, %loop.2 ]
+ %iv.2.next = add i32 %p.2, %iv.2
+ %iv.1.next = add nuw nsw i32 %iv.1, 1
+ %ec.2 = icmp ult i32 %iv.1.next, 12345
+ br i1 %ec.2, label %loop.2, label %exit
+
+exit:
+ %lcssa.2 = phi i32 [ %iv.2.next, %loop.2 ]
+ ret i32 %lcssa.2
+}
+
+declare void @fn(i32)
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