[llvm] r303747 - Revert "[SCEV] Do not fold dominated SCEVUnknown into AddRecExpr start"
Diana Picus via llvm-commits
llvm-commits at lists.llvm.org
Wed May 24 07:16:04 PDT 2017
Author: rovka
Date: Wed May 24 09:16:04 2017
New Revision: 303747
URL: http://llvm.org/viewvc/llvm-project?rev=303747&view=rev
Log:
Revert "[SCEV] Do not fold dominated SCEVUnknown into AddRecExpr start"
This reverts commit r303730 because it broke all the buildbots.
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/lib/Analysis/ScalarEvolution.cpp
llvm/trunk/test/Analysis/IVUsers/quadradic-exit-value.ll
llvm/trunk/test/Analysis/ScalarEvolution/different-loops-recs.ll
llvm/trunk/test/Transforms/LoopStrengthReduce/X86/incorrect-offset-scaling.ll
llvm/trunk/test/Transforms/LoopStrengthReduce/lsr-expand-quadratic.ll
llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Wed May 24 09:16:04 2017
@@ -1533,12 +1533,6 @@ public:
/// specified loop.
bool isLoopInvariant(const SCEV *S, const Loop *L);
- /// Determine if the SCEV can be evaluated at loop's entry. It is true if it
- /// doesn't depend on a SCEVUnknown of an instruction which is dominated by
- /// the header of loop L.
- bool isAvailableAtLoopEntry(const SCEV *S, const Loop *L, DominatorTree &DT,
- LoopInfo &LI);
-
/// Return true if the given SCEV changes value in a known way in the
/// specified loop. This property being true implies that the value is
/// variant in the loop AND that we can emit an expression to compute the
Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Wed May 24 09:16:04 2017
@@ -2178,63 +2178,6 @@ StrengthenNoWrapFlags(ScalarEvolution *S
return Flags;
}
-bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L,
- DominatorTree &DT, LoopInfo &LI) {
- if (!isLoopInvariant(S, L))
- return false;
- // If a value depends on a SCEVUnknown which is defined after the loop, we
- // conservatively assume that we cannot calculate it at the loop's entry.
- struct FindDominatedSCEVUnknown {
- bool Found = false;
- const Loop *L;
- DominatorTree &DT;
- LoopInfo &LI;
-
- FindDominatedSCEVUnknown(const Loop *L, DominatorTree &DT, LoopInfo &LI)
- : L(L), DT(DT), LI(LI) {}
-
- bool checkSCEVUnknown(const SCEVUnknown *SU) {
- if (auto *I = dyn_cast<Instruction>(SU->getValue())) {
- if (DT.dominates(L->getHeader(), I->getParent()))
- Found = true;
- else
- assert(DT.dominates(I->getParent(), L->getHeader()) &&
- "No dominance relationship between SCEV and loop?");
- }
- return false;
- }
-
- bool follow(const SCEV *S) {
- switch (static_cast<SCEVTypes>(S->getSCEVType())) {
- case scConstant:
- return false;
- case scAddRecExpr:
- case scTruncate:
- case scZeroExtend:
- case scSignExtend:
- case scAddExpr:
- case scMulExpr:
- case scUMaxExpr:
- case scSMaxExpr:
- case scUDivExpr:
- return true;
- case scUnknown:
- return checkSCEVUnknown(cast<SCEVUnknown>(S));
- case scCouldNotCompute:
- llvm_unreachable("Attempt to use a SCEVCouldNotCompute object!");
- }
- return false;
- }
-
- bool isDone() { return Found; }
- };
-
- FindDominatedSCEVUnknown FSU(L, DT, LI);
- SCEVTraversal<FindDominatedSCEVUnknown> ST(FSU);
- ST.visitAll(S);
- return !FSU.Found;
-}
-
/// Get a canonical add expression, or something simpler if possible.
const SCEV *ScalarEvolution::getAddExpr(SmallVectorImpl<const SCEV *> &Ops,
SCEV::NoWrapFlags Flags,
@@ -2516,7 +2459,7 @@ const SCEV *ScalarEvolution::getAddExpr(
const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
const Loop *AddRecLoop = AddRec->getLoop();
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (isAvailableAtLoopEntry(Ops[i], AddRecLoop, DT, LI)) {
+ if (isLoopInvariant(Ops[i], AddRecLoop)) {
LIOps.push_back(Ops[i]);
Ops.erase(Ops.begin()+i);
--i; --e;
@@ -2791,7 +2734,7 @@ const SCEV *ScalarEvolution::getMulExpr(
const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
const Loop *AddRecLoop = AddRec->getLoop();
for (unsigned i = 0, e = Ops.size(); i != e; ++i)
- if (isAvailableAtLoopEntry(Ops[i], AddRecLoop, DT, LI)) {
+ if (isLoopInvariant(Ops[i], AddRecLoop)) {
LIOps.push_back(Ops[i]);
Ops.erase(Ops.begin()+i);
--i; --e;
Modified: llvm/trunk/test/Analysis/IVUsers/quadradic-exit-value.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/IVUsers/quadradic-exit-value.ll?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/IVUsers/quadradic-exit-value.ll (original)
+++ llvm/trunk/test/Analysis/IVUsers/quadradic-exit-value.ll Wed May 24 09:16:04 2017
@@ -30,47 +30,13 @@ exit:
ret i64 %r
}
-; PR15470: LSR miscompile. The test1 function should return '1'.
-; It is valid to fold SCEVUnknown into the recurrence because it
-; was defined before the loop.
-;
-; SCEV does not know how to denormalize chained recurrences, so make
-; sure they aren't marked as post-inc users.
-;
-; CHECK-LABEL: IV Users for loop %test1.loop
-; CHECK-NO-LCSSA: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test1.loop> (post-inc with loop %test1.loop) in %f = ashr i32 %sext.us, 24
-define i32 @test1(i1 %cond) {
-entry:
- %sub.us = select i1 %cond, i32 0, i32 0
- br label %test1.loop
-
-test1.loop:
- %inc1115.us = phi i32 [ 0, %entry ], [ %inc11.us, %test1.loop ]
- %inc11.us = add nsw i32 %inc1115.us, 1
- %cmp.us = icmp slt i32 %inc11.us, 2
- br i1 %cmp.us, label %test1.loop, label %for.end
-
-for.end:
- %tobool.us = icmp eq i32 %inc1115.us, 0
- %mul.us = shl i32 %inc1115.us, 24
- %sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
- %sext.us = mul i32 %mul.us, %sub.cond.us
- %f = ashr i32 %sext.us, 24
- br label %exit
-
-exit:
- ret i32 %f
-}
-
; PR15470: LSR miscompile. The test2 function should return '1'.
-; It is illegal to fold SCEVUnknown (sext.us) into the recurrence
-; because it is defined after the loop where this recurrence belongs.
;
; SCEV does not know how to denormalize chained recurrences, so make
; sure they aren't marked as post-inc users.
;
; CHECK-LABEL: IV Users for loop %test2.loop
-; CHECK-NO-LCSSA: %sub.cond.us = ((-1 * %sub.us)<nsw> + {0,+,1}<nuw><nsw><%test2.loop>) (post-inc with loop %test2.loop) in %sext.us = mul i32 %mul.us, %sub.cond.us
+; CHECK-NO-LCSSA: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test2.loop> (post-inc with loop %test2.loop) in %f = ashr i32 %sext.us, 24
define i32 @test2() {
entry:
br label %test2.loop
Modified: llvm/trunk/test/Analysis/ScalarEvolution/different-loops-recs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/ScalarEvolution/different-loops-recs.ll?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/ScalarEvolution/different-loops-recs.ll (original)
+++ llvm/trunk/test/Analysis/ScalarEvolution/different-loops-recs.ll Wed May 24 09:16:04 2017
@@ -220,8 +220,7 @@ exit:
; Mix of previous use cases that demonstrates %s3 can be incorrectly treated as
; a recurrence of loop1 because of operands order if we pick recurrencies in an
-; incorrect order. It also shows that we cannot safely fold v1 (SCEVUnknown)
-; because we cannot prove for sure that it doesn't use Phis of loop 2.
+; incorrect order.
define void @test_03(i32 %a, i32 %b, i32 %c, i32* %p) {
@@ -229,9 +228,9 @@ define void @test_03(i32 %a, i32 %b, i32
; CHECK: %v1 = load i32, i32* %p
; CHECK-NEXT: --> %v1
; CHECK: %s1 = add i32 %phi1, %v1
-; CHECK-NEXT: --> ({%a,+,1}<%loop1> + %v1)
+; CHECK-NEXT: --> {(%a + %v1),+,1}<%loop1>
; CHECK: %s2 = add i32 %s1, %b
-; CHECK-NEXT: --> ({(%a + %b),+,1}<%loop1> + %v1)
+; CHECK-NEXT: --> {(%a + %b + %v1),+,1}<%loop1>
; CHECK: %s3 = add i32 %s2, %phi2
; CHECK-NEXT: --> ({{{{}}((2 * %a) + %b),+,1}<%loop1>,+,2}<%loop2> + %v1)
@@ -453,60 +452,3 @@ exit:
%s6 = add i32 %phi3, %phi2
ret void
}
-
-; Make sure that a complicated Phi does not get folded with rec's start value
-; of a loop which is above.
-define void @test_08() {
-
-; CHECK-LABEL: Classifying expressions for: @test_08
-; CHECK: %tmp11 = add i64 %iv.2.2, %iv.2.1
-; CHECK-NEXT: --> ({0,+,-1}<nsw><%loop_2> + %iv.2.1)
-; CHECK: %tmp12 = trunc i64 %tmp11 to i32
-; CHECK-NEXT: --> (trunc i64 ({0,+,-1}<nsw><%loop_2> + %iv.2.1) to i32)
-; CHECK: %tmp14 = mul i32 %tmp12, %tmp7
-; CHECK-NEXT: --> ((trunc i64 ({0,+,-1}<nsw><%loop_2> + %iv.2.1) to i32) * {-1,+,-1}<%loop_1>)
-; CHECK: %tmp16 = mul i64 %iv.2.1, %iv.1.1
-; CHECK-NEXT: --> ({2,+,1}<nuw><nsw><%loop_1> * %iv.2.1)
-
-entry:
- br label %loop_1
-
-loop_1:
- %iv.1.1 = phi i64 [ 2, %entry ], [ %iv.1.1.next, %loop_1_back_branch ]
- %iv.1.2 = phi i32 [ -1, %entry ], [ %iv.1.2.next, %loop_1_back_branch ]
- br label %loop_1_exit
-
-dead:
- br label %loop_1_exit
-
-loop_1_exit:
- %tmp5 = icmp sgt i64 %iv.1.1, 2
- br i1 %tmp5, label %loop_2_preheader, label %loop_1_back_branch
-
-loop_1_back_branch:
- %iv.1.1.next = add nuw nsw i64 %iv.1.1, 1
- %iv.1.2.next = add nsw i32 %iv.1.2, 1
- br label %loop_1
-
-loop_2_preheader:
- %tmp6 = sub i64 1, %iv.1.1
- %tmp7 = trunc i64 %tmp6 to i32
- br label %loop_2
-
-loop_2:
- %iv.2.1 = phi i64 [ 0, %loop_2_preheader ], [ %tmp16, %loop_2 ]
- %iv.2.2 = phi i64 [ 0, %loop_2_preheader ], [ %iv.2.2.next, %loop_2 ]
- %iv.2.3 = phi i64 [ 2, %loop_2_preheader ], [ %iv.2.3.next, %loop_2 ]
- %tmp11 = add i64 %iv.2.2, %iv.2.1
- %tmp12 = trunc i64 %tmp11 to i32
- %tmp14 = mul i32 %tmp12, %tmp7
- %tmp16 = mul i64 %iv.2.1, %iv.1.1
- %iv.2.3.next = add nuw nsw i64 %iv.2.3, 1
- %iv.2.2.next = add nsw i64 %iv.2.2, -1
- %tmp17 = icmp slt i64 %iv.2.3.next, %iv.1.1
- br i1 %tmp17, label %loop_2, label %exit
-
-exit:
- %tmp10 = add i32 %iv.1.2, 3
- ret void
-}
Modified: llvm/trunk/test/Transforms/LoopStrengthReduce/X86/incorrect-offset-scaling.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/X86/incorrect-offset-scaling.ll?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/X86/incorrect-offset-scaling.ll (original)
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/X86/incorrect-offset-scaling.ll Wed May 24 09:16:04 2017
@@ -25,7 +25,7 @@ L2:
if6: ; preds = %idxend.8
%r2 = add i64 %0, -1
%r3 = load i64, i64* %1, align 8
-; CHECK: %r2 = add i64 %0, -1
+; CHECK-NOT: %r2
; CHECK: %r3 = load i64
br label %ib
@@ -36,11 +36,13 @@ ib:
%r4 = mul i64 %r3, %r0
%r5 = add i64 %r2, %r4
%r6 = icmp ult i64 %r5, undef
-; CHECK: %r4 = mul i64 %r3, %lsr.iv
-; CHECK: %r5 = add i64 %r2, %r4
-; CHECK: %r6 = icmp ult i64 %r5, undef
-; CHECK: %r7 = getelementptr i64, i64* undef, i64 %r5
+; CHECK: [[MUL1:%[0-9]+]] = mul i64 %lsr.iv, %r3
+; CHECK: [[ADD1:%[0-9]+]] = add i64 [[MUL1]], -1
+; CHECK: add i64 %{{.}}, [[ADD1]]
+; CHECK: %r6
%r7 = getelementptr i64, i64* undef, i64 %r5
store i64 1, i64* %r7, align 8
+; CHECK: [[MUL2:%[0-9]+]] = mul i64 %lsr.iv, %r3
+; CHECK: [[ADD2:%[0-9]+]] = add i64 [[MUL2]], -1
br label %L
}
Modified: llvm/trunk/test/Transforms/LoopStrengthReduce/lsr-expand-quadratic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/lsr-expand-quadratic.ll?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/lsr-expand-quadratic.ll (original)
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/lsr-expand-quadratic.ll Wed May 24 09:16:04 2017
@@ -7,23 +7,16 @@ target triple = "x86_64-apple-macosx"
;
; SCEV expander cannot expand quadratic recurrences outside of the
; loop. This recurrence depends on %sub.us, so can't be expanded.
-; We cannot fold SCEVUnknown (sub.us) with recurrences since it is
-; declared after the loop.
;
; CHECK-LABEL: @test2
; CHECK-LABEL: test2.loop:
-; CHECK: %lsr.iv1 = phi i32 [ %lsr.iv.next2, %test2.loop ], [ -16777216, %entry ]
-; CHECK: %lsr.iv = phi i32 [ %lsr.iv.next, %test2.loop ], [ -1, %entry ]
-; CHECK: %lsr.iv.next = add nsw i32 %lsr.iv, 1
-; CHECK: %lsr.iv.next2 = add nsw i32 %lsr.iv1, 16777216
+; CHECK: %lsr.iv = phi i32 [ %lsr.iv.next, %test2.loop ], [ -16777216, %entry ]
+; CHECK: %lsr.iv.next = add nsw i32 %lsr.iv, 16777216
;
; CHECK-LABEL: for.end:
-; CHECK: %tobool.us = icmp eq i32 %lsr.iv.next2, 0
-; CHECK: %sub.us = select i1 %tobool.us, i32 0, i32 0
-; CHECK: %1 = sub i32 0, %sub.us
-; CHECK: %2 = add i32 %1, %lsr.iv.next
-; CHECK: %sext.us = mul i32 %lsr.iv.next2, %2
-; CHECK: %f = ashr i32 %sext.us, 24
+; CHECK: %sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
+; CHECK: %sext.us = mul i32 %lsr.iv.next, %sub.cond.us
+; CHECK: %f = ashr i32 %sext.us, 24
; CHECK: ret i32 %f
define i32 @test2() {
entry:
Modified: llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll?rev=303747&r1=303746&r2=303747&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll (original)
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/post-inc-icmpzero.ll Wed May 24 09:16:04 2017
@@ -25,8 +25,6 @@ define void @_Z15IntegerToStringjjR7Vect
entry:
%buffer = alloca [33 x i16], align 16
%add.ptr = getelementptr inbounds [33 x i16], [33 x i16]* %buffer, i64 0, i64 33
- %sub.ptr.lhs.cast = ptrtoint i16* %add.ptr to i64
- %sub.ptr.rhs.cast = ptrtoint i16* %add.ptr to i64
br label %do.body
do.body: ; preds = %do.body, %entry
@@ -48,6 +46,8 @@ do.body:
do.end: ; preds = %do.body
%xap.0 = inttoptr i64 %0 to i1*
%cap.0 = ptrtoint i1* %xap.0 to i64
+ %sub.ptr.lhs.cast = ptrtoint i16* %add.ptr to i64
+ %sub.ptr.rhs.cast = ptrtoint i16* %incdec.ptr to i64
%sub.ptr.sub = sub i64 %sub.ptr.lhs.cast, %sub.ptr.rhs.cast
%sub.ptr.div39 = lshr exact i64 %sub.ptr.sub, 1
%conv11 = trunc i64 %sub.ptr.div39 to i32
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