[llvm] 8fdac7c - Revert D71539 "Recommit "[SCEV] Look through single value PHIs.""
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 21 17:21:53 PDT 2020
Author: Fangrui Song
Date: 2020-09-21T17:21:43-07:00
New Revision: 8fdac7cb7abbeeaed016ef9eb7a087458e41e33f
URL: https://github.com/llvm/llvm-project/commit/8fdac7cb7abbeeaed016ef9eb7a087458e41e33f
DIFF: https://github.com/llvm/llvm-project/commit/8fdac7cb7abbeeaed016ef9eb7a087458e41e33f.diff
LOG: Revert D71539 "Recommit "[SCEV] Look through single value PHIs.""
This reverts commit 11dccf8d3aa5d55210f8b886fb21926c7a8353ca.
A bootstrapped clang crashes (due to ArrayRef::front called on an empty
ArrayRef) when compiling some files. Very strangely, this only reproduces with
modules.
```
13 0x0000564d3349e968 llvm::ArrayRef<llvm::BasicBlock*>::front() const /proc/self/cwd/llvm/include/llvm/ADT/ArrayRef.h:160:7
14 0x0000564d3349e896 llvm::LoopBase<llvm::BasicBlock, llvm::Loop>::getHeader() const /proc/self/cwd/llvm/include/llvm/Analysis/LoopInfo.h:104:50
15 0x0000564d3349fd9d llvm::LoopBase<llvm::BasicBlock, llvm::Loop>::getLoopLatch() const /proc/self/cwd/llvm/include/llvm/Analysis/LoopInfoImpl.h:210:11
16 0x0000564d33593c8a llvm::ScalarEvolution::computeBackedgeTakenCount(llvm::Loop const*, bool) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:6933:15
17 0x0000564d33592ebc llvm::ScalarEvolution::getBackedgeTakenInfo(llvm::Loop const*) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:0:30
18 0x0000564d33593a54 llvm::ScalarEvolution::getBackedgeTakenCount(llvm::Loop const*, llvm::ScalarEvolution::ExitCountKind) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:6487:36
19 0x0000564d32be2402 llvm::ScalarEvolution::getConstantMaxBackedgeTakenCount(llvm::Loop const*) /proc/self/cwd/llvm/include/llvm/Analysis/ScalarEvolution.h:768:5
20 0x0000564d33590807 llvm::ScalarEvolution::getRangeRef(llvm::SCEV const*, llvm::ScalarEvolution::RangeSignHint) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:5495:19
21 0x0000564d320abab7 llvm::ScalarEvolution::getSignedRange(llvm::SCEV const*) /proc/self/cwd/llvm/include/llvm/Analysis/ScalarEvolution.h:840:12
22 0x0000564d335a03aa llvm::ScalarEvolution::isKnownPredicateViaConstantRanges(llvm::CmpInst::Predicate, llvm::SCEV const*, llvm::SCEV const*) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:9239:60
23 0x0000564d33586a80 llvm::ScalarEvolution::isKnownViaNonRecursiveReasoning(llvm::CmpInst::Predicate, llvm::SCEV const*, llvm::SCEV const*) /proc/self/cwd/llvm/lib/Analysis/ScalarEvolution.cpp:10284:60
```
Added:
Modified:
llvm/lib/Analysis/ScalarEvolution.cpp
llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
llvm/test/Transforms/LoopStrengthReduce/funclet.ll
Removed:
################################################################################
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 46664192d70c..3bf7f2036136 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5114,8 +5114,13 @@ const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
if (const SCEV *S = createNodeFromSelectLikePHI(PN))
return S;
+ // If the PHI has a single incoming value, follow that value, unless the
+ // PHI's incoming blocks are in a
diff erent loop, in which case doing so
+ // risks breaking LCSSA form. Instcombine would normally zap these, but
+ // it doesn't have DominatorTree information, so it may miss cases.
if (Value *V = SimplifyInstruction(PN, {getDataLayout(), &TLI, &DT, &AC}))
- return getSCEV(V);
+ if (LI.replacementPreservesLCSSAForm(PN, V))
+ return getSCEV(V);
// If it's not a loop phi, we can't handle it yet.
return getUnknown(PN);
diff --git a/llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll b/llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
index 1535f81e13eb..525b8df764b9 100644
--- a/llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
+++ b/llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
@@ -58,9 +58,9 @@ b2: ; preds = %b1
; CHECK-NEXT: %v6 = add nuw nsw i32 %v1, 1
; CHECK-NEXT: --> {4,+,1}<nuw><nsw><%b1> U: [4,7) S: [4,7) Exits: 6 LoopDispositions: { %b1: Computable }
; CHECK-NEXT: %v7 = phi i32 [ %v1, %b1 ]
-; CHECK-NEXT: --> {3,+,1}<nuw><nsw><%b1> U: [3,6) S: [3,6) --> 5 U: [5,6) S: [5,6)
+; CHECK-NEXT: --> %v7 U: [3,6) S: [3,6)
; CHECK-NEXT: %v8 = phi i16 [ %v3, %b1 ]
-; CHECK-NEXT: --> {3,+,4,+,1}<%b1> U: full-set S: full-set --> 12 U: [12,13) S: [12,13)
+; CHECK-NEXT: --> %v8 U: full-set S: full-set
; CHECK-NEXT: Determining loop execution counts for: @f1
; CHECK-NEXT: Loop %b3: <multiple exits> Unpredictable backedge-taken count.
; CHECK-NEXT: Loop %b3: Unpredictable max backedge-taken count.
diff --git a/llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll b/llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
index 7596e9d4948d..331bf31e9e78 100644
--- a/llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
+++ b/llvm/test/Analysis/ScalarEvolution/solve-quadratic-overflow.ll
@@ -13,11 +13,11 @@
; CHECK-NEXT: %v3 = mul i16 %v2, %v2
; CHECK-NEXT: --> {1,+,3,+,2}<%b1> U: full-set S: full-set Exits: 0 LoopDispositions: { %b1: Computable }
; CHECK-NEXT: %v5 = phi i16 [ %v2, %b1 ]
-; CHECK-NEXT: --> {-1,+,-1}<%b1> U: [-256,0) S: [-256,0) --> -256 U: [-256,-255) S: [-256,-255)
+; CHECK-NEXT: --> %v5 U: [-256,0) S: [-256,0)
; CHECK-NEXT: %v6 = phi i16 [ %v3, %b1 ]
-; CHECK-NEXT: --> {1,+,3,+,2}<%b1> U: full-set S: full-set --> 0 U: [0,1) S: [0,1)
+; CHECK-NEXT: --> %v6 U: full-set S: full-set
; CHECK-NEXT: %v7 = sext i16 %v5 to i32
-; CHECK-NEXT: --> {-1,+,-1}<nsw><%b1> U: [-256,0) S: [-256,0) --> -256 U: [-256,-255) S: [-256,-255)
+; CHECK-NEXT: --> (sext i16 %v5 to i32) U: [-256,0) S: [-256,0)
; CHECK-NEXT: Determining loop execution counts for: @f0
; CHECK-NEXT: Loop %b1: backedge-taken count is 255
; CHECK-NEXT: Loop %b1: max backedge-taken count is 255
diff --git a/llvm/test/Transforms/LoopStrengthReduce/funclet.ll b/llvm/test/Transforms/LoopStrengthReduce/funclet.ll
index ca0a86635ec0..0f725a13b207 100644
--- a/llvm/test/Transforms/LoopStrengthReduce/funclet.ll
+++ b/llvm/test/Transforms/LoopStrengthReduce/funclet.ll
@@ -15,21 +15,25 @@ define void @f() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[THROW:%.*]]
; CHECK: throw:
+; CHECK-NEXT: [[TMP96:%.*]] = getelementptr inbounds i8, i8* undef, i32 1
; CHECK-NEXT: invoke void @reserve()
; CHECK-NEXT: to label [[THROW]] unwind label [[PAD:%.*]]
; CHECK: pad:
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8* [ [[TMP96]], [[THROW]] ]
; CHECK-NEXT: [[CS:%.*]] = catchswitch within none [label %unreachable] unwind label [[BLAH2:%.*]]
; CHECK: unreachable:
; CHECK-NEXT: [[TMP0:%.*]] = catchpad within [[CS]] []
; CHECK-NEXT: unreachable
; CHECK: blah2:
; CHECK-NEXT: [[CLEANUPPADI4_I_I_I:%.*]] = cleanuppad within none []
+; CHECK-NEXT: [[PHI21:%.*]] = ptrtoint i8* [[PHI2]] to i32
+; CHECK-NEXT: [[TMP1:%.*]] = sub i32 1, [[PHI21]]
+; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, i8* undef, i32 [[TMP1]]
; CHECK-NEXT: br label [[LOOP_BODY:%.*]]
; CHECK: loop_body:
-; CHECK-NEXT: [[LSR_IV:%.*]] = phi i32 [ [[LSR_IV_NEXT:%.*]], [[ITER:%.*]] ], [ 0, [[BLAH2]] ]
-; CHECK-NEXT: [[LSR_IV_NEXT]] = add nuw nsw i32 [[LSR_IV]], -1
-; CHECK-NEXT: [[LSR_IV_NEXT1:%.*]] = inttoptr i32 [[LSR_IV_NEXT]] to i8*
-; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[LSR_IV_NEXT1]], null
+; CHECK-NEXT: [[LSR_IV:%.*]] = phi i8* [ [[SCEVGEP2:%.*]], [[ITER:%.*]] ], [ [[SCEVGEP]], [[BLAH2]] ]
+; CHECK-NEXT: [[SCEVGEP2]] = getelementptr i8, i8* [[LSR_IV]], i32 -1
+; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[SCEVGEP2]], null
; CHECK-NEXT: br i1 [[TMP100]], label [[UNWIND_OUT:%.*]], label [[ITER]]
; CHECK: iter:
; CHECK-NEXT: br i1 true, label [[UNWIND_OUT]], label [[LOOP_BODY]]
@@ -74,25 +78,29 @@ define void @g() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[THROW:%.*]]
; CHECK: throw:
+; CHECK-NEXT: [[TMP96:%.*]] = getelementptr inbounds i8, i8* undef, i32 1
; CHECK-NEXT: invoke void @reserve()
; CHECK-NEXT: to label [[THROW]] unwind label [[PAD:%.*]]
; CHECK: pad:
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8* [ [[TMP96]], [[THROW]] ]
; CHECK-NEXT: [[CS:%.*]] = catchswitch within none [label [[UNREACHABLE:%.*]], label %blah] unwind to caller
; CHECK: unreachable:
; CHECK-NEXT: [[TMP0:%.*]] = catchpad within [[CS]] []
; CHECK-NEXT: unreachable
; CHECK: blah:
; CHECK-NEXT: [[CATCHPAD:%.*]] = catchpad within [[CS]] []
+; CHECK-NEXT: [[PHI21:%.*]] = ptrtoint i8* [[PHI2]] to i32
+; CHECK-NEXT: [[TMP1:%.*]] = sub i32 1, [[PHI21]]
+; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, i8* undef, i32 [[TMP1]]
; CHECK-NEXT: br label [[LOOP_BODY:%.*]]
; CHECK: unwind_out:
; CHECK-NEXT: catchret from [[CATCHPAD]] to label [[LEAVE:%.*]]
; CHECK: leave:
; CHECK-NEXT: ret void
; CHECK: loop_body:
-; CHECK-NEXT: [[LSR_IV:%.*]] = phi i32 [ [[LSR_IV_NEXT:%.*]], [[ITER:%.*]] ], [ 0, [[BLAH:%.*]] ]
-; CHECK-NEXT: [[LSR_IV_NEXT]] = add nuw nsw i32 [[LSR_IV]], -1
-; CHECK-NEXT: [[LSR_IV_NEXT1:%.*]] = inttoptr i32 [[LSR_IV_NEXT]] to i8*
-; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[LSR_IV_NEXT1]], null
+; CHECK-NEXT: [[LSR_IV:%.*]] = phi i8* [ [[SCEVGEP2:%.*]], [[ITER:%.*]] ], [ [[SCEVGEP]], [[BLAH:%.*]] ]
+; CHECK-NEXT: [[SCEVGEP2]] = getelementptr i8, i8* [[LSR_IV]], i32 -1
+; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[SCEVGEP2]], null
; CHECK-NEXT: br i1 [[TMP100]], label [[UNWIND_OUT:%.*]], label [[ITER]]
; CHECK: iter:
; CHECK-NEXT: br i1 true, label [[UNWIND_OUT]], label [[LOOP_BODY]]
@@ -138,6 +146,7 @@ define void @h() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[THROW:%.*]]
; CHECK: throw:
+; CHECK-NEXT: [[TMP96:%.*]] = getelementptr inbounds i8, i8* undef, i32 1
; CHECK-NEXT: invoke void @reserve()
; CHECK-NEXT: to label [[THROW]] unwind label [[PAD:%.*]]
; CHECK: pad:
@@ -146,17 +155,20 @@ define void @h() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: [[TMP0:%.*]] = catchpad within [[CS]] []
; CHECK-NEXT: unreachable
; CHECK: blug:
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8* [ [[TMP96]], [[PAD]] ]
; CHECK-NEXT: [[CATCHPAD:%.*]] = catchpad within [[CS]] []
+; CHECK-NEXT: [[PHI21:%.*]] = ptrtoint i8* [[PHI2]] to i32
+; CHECK-NEXT: [[TMP1:%.*]] = sub i32 1, [[PHI21]]
+; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, i8* undef, i32 [[TMP1]]
; CHECK-NEXT: br label [[LOOP_BODY:%.*]]
; CHECK: unwind_out:
; CHECK-NEXT: catchret from [[CATCHPAD]] to label [[LEAVE:%.*]]
; CHECK: leave:
; CHECK-NEXT: ret void
; CHECK: loop_body:
-; CHECK-NEXT: [[LSR_IV:%.*]] = phi i32 [ [[LSR_IV_NEXT:%.*]], [[ITER:%.*]] ], [ 0, [[BLUG:%.*]] ]
-; CHECK-NEXT: [[LSR_IV_NEXT]] = add nuw nsw i32 [[LSR_IV]], -1
-; CHECK-NEXT: [[LSR_IV_NEXT1:%.*]] = inttoptr i32 [[LSR_IV_NEXT]] to i8*
-; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[LSR_IV_NEXT1]], null
+; CHECK-NEXT: [[LSR_IV:%.*]] = phi i8* [ [[SCEVGEP2:%.*]], [[ITER:%.*]] ], [ [[SCEVGEP]], [[BLUG:%.*]] ]
+; CHECK-NEXT: [[SCEVGEP2]] = getelementptr i8, i8* [[LSR_IV]], i32 -1
+; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[SCEVGEP2]], null
; CHECK-NEXT: br i1 [[TMP100]], label [[UNWIND_OUT:%.*]], label [[ITER]]
; CHECK: iter:
; CHECK-NEXT: br i1 true, label [[UNWIND_OUT]], label [[LOOP_BODY]]
@@ -202,9 +214,11 @@ define void @i() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[THROW:%.*]]
; CHECK: throw:
+; CHECK-NEXT: [[TMP96:%.*]] = getelementptr inbounds i8, i8* undef, i32 1
; CHECK-NEXT: invoke void @reserve()
; CHECK-NEXT: to label [[THROW]] unwind label [[CATCHPAD:%.*]]
; CHECK: catchpad:
+; CHECK-NEXT: [[PHI2:%.*]] = phi i8* [ [[TMP96]], [[THROW]] ]
; CHECK-NEXT: [[CS:%.*]] = catchswitch within none [label %cp_body] unwind label [[CLEANUPPAD:%.*]]
; CHECK: cp_body:
; CHECK-NEXT: [[TMP0:%.*]] = catchpad within [[CS]] []
@@ -213,12 +227,14 @@ define void @i() personality i32 (...)* @_except_handler3 {
; CHECK-NEXT: [[TMP1:%.*]] = cleanuppad within none []
; CHECK-NEXT: br label [[LOOP_HEAD]]
; CHECK: loop_head:
+; CHECK-NEXT: [[PHI21:%.*]] = ptrtoint i8* [[PHI2]] to i32
+; CHECK-NEXT: [[TMP2:%.*]] = sub i32 1, [[PHI21]]
+; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, i8* undef, i32 [[TMP2]]
; CHECK-NEXT: br label [[LOOP_BODY:%.*]]
; CHECK: loop_body:
-; CHECK-NEXT: [[LSR_IV:%.*]] = phi i32 [ [[LSR_IV_NEXT:%.*]], [[ITER:%.*]] ], [ 0, [[LOOP_HEAD]] ]
-; CHECK-NEXT: [[LSR_IV_NEXT]] = add nuw nsw i32 [[LSR_IV]], -1
-; CHECK-NEXT: [[LSR_IV_NEXT1:%.*]] = inttoptr i32 [[LSR_IV_NEXT]] to i8*
-; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[LSR_IV_NEXT1]], null
+; CHECK-NEXT: [[LSR_IV:%.*]] = phi i8* [ [[SCEVGEP2:%.*]], [[ITER:%.*]] ], [ [[SCEVGEP]], [[LOOP_HEAD]] ]
+; CHECK-NEXT: [[SCEVGEP2]] = getelementptr i8, i8* [[LSR_IV]], i32 -1
+; CHECK-NEXT: [[TMP100:%.*]] = icmp eq i8* [[SCEVGEP2]], null
; CHECK-NEXT: br i1 [[TMP100]], label [[UNWIND_OUT:%.*]], label [[ITER]]
; CHECK: iter:
; CHECK-NEXT: br i1 true, label [[UNWIND_OUT]], label [[LOOP_BODY]]
More information about the llvm-commits
mailing list