[llvm] e302fa8 - [LoopUnroll] Forget exit values when making changes.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 18 07:14:57 PDT 2022
Author: Florian Hahn
Date: 2022-10-18T15:12:24+01:00
New Revision: e302fa89aa45afceedb711a264cfc486395aca17
URL: https://github.com/llvm/llvm-project/commit/e302fa89aa45afceedb711a264cfc486395aca17
DIFF: https://github.com/llvm/llvm-project/commit/e302fa89aa45afceedb711a264cfc486395aca17.diff
LOG: [LoopUnroll] Forget exit values when making changes.
When unrolling, the exit values in LCSSA phis will get updated.
Invalidate cached SCEV values for those phis in case SCEV looked through
a exit phi.
Fixes #58340.
Added:
Modified:
llvm/lib/Transforms/Utils/LoopUnroll.cpp
llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 6d6c3db034cae..fd874db6981b2 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -578,6 +578,7 @@ LoopUnrollResult llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
if (It != LastValueMap.end())
Incoming = It->second;
PHI.addIncoming(Incoming, New);
+ SE->forgetValue(&PHI);
}
}
// Keep track of new headers and latches as we create them, so that
diff --git a/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll b/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
index 8cf482953f646..0c9f9dbbe4a96 100644
--- a/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
+++ b/llvm/test/Transforms/LoopUnroll/scev-forget-exit-phis.ll
@@ -18,14 +18,13 @@ define i8 @test_pr58340(ptr %dst.1, ptr %dst.2) {
; CHECK-NEXT: store i32 [[SEL_1]], ptr [[DST_1:%.*]], align 4
; CHECK-NEXT: br label [[INNER_1_LATCH:%.*]]
; CHECK: inner.2.header.preheader:
-; CHECK-NEXT: [[SEL_1_LCSSA:%.*]] = phi i32 [ [[SEL_1_1:%.*]], [[MERGE_1:%.*]] ]
; CHECK-NEXT: br label [[INNER_2_HEADER:%.*]]
; CHECK: inner.1.latch:
-; CHECK-NEXT: br i1 false, label [[MERGE_1]], label [[THEN_1:%.*]]
+; CHECK-NEXT: br i1 false, label [[MERGE_1:%.*]], label [[THEN_1:%.*]]
; CHECK: then.1:
; CHECK-NEXT: br label [[MERGE_1]]
; CHECK: merge.1:
-; CHECK-NEXT: [[SEL_1_1]] = phi i32 [ 0, [[INNER_1_LATCH]] ], [ 2, [[THEN_1]] ]
+; CHECK-NEXT: [[SEL_1_1:%.*]] = phi i32 [ 0, [[INNER_1_LATCH]] ], [ 2, [[THEN_1]] ]
; CHECK-NEXT: store i32 [[SEL_1_1]], ptr [[DST_1]], align 4
; CHECK-NEXT: br i1 false, label [[INNER_1_LATCH_1:%.*]], label [[INNER_2_HEADER_PREHEADER:%.*]]
; CHECK: inner.1.latch.1:
@@ -33,14 +32,8 @@ define i8 @test_pr58340(ptr %dst.1, ptr %dst.2) {
; CHECK: inner.2.header:
; CHECK-NEXT: br label [[INNER_3:%.*]]
; CHECK: inner.3:
-; CHECK-NEXT: [[SEL_2:%.*]] = phi i64 [ [[SEL_1_EXT:%.*]], [[INNER_3]] ], [ 0, [[INNER_2_HEADER]] ]
-; CHECK-NEXT: [[C_1:%.*]] = icmp ult i32 [[SEL_1_LCSSA]], 1
-; CHECK-NEXT: [[SEL_1_EXT]] = sext i32 [[SEL_1_LCSSA]] to i64
-; CHECK-NEXT: br i1 [[C_1]], label [[INNER_3]], label [[INNER_2_LATCH:%.*]]
-; CHECK: inner.2.latch:
-; CHECK-NEXT: [[SEL_2_LCSSA:%.*]] = phi i64 [ [[SEL_2]], [[INNER_3]] ]
; CHECK-NEXT: store i32 0, ptr [[DST_1]], align 4
-; CHECK-NEXT: store i64 [[SEL_2_LCSSA]], ptr [[DST_2:%.*]], align 8
+; CHECK-NEXT: store i64 0, ptr [[DST_2:%.*]], align 8
; CHECK-NEXT: call void @clobber()
; CHECK-NEXT: br label [[OUTER_HEADER]]
;
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