[llvm] r198631 - Reapply r198478 "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things."
Andrew Trick
atrick at apple.com
Mon Jan 6 11:43:14 PST 2014
Author: atrick
Date: Mon Jan 6 13:43:14 2014
New Revision: 198631
URL: http://llvm.org/viewvc/llvm-project?rev=198631&view=rev
Log:
Reapply r198478 "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things."
Now with a fix for PR18384: ValueHandleBase::ValueIsDeleted.
We need to invalidate SCEV's loop info when we delete a block, even if no values are hoisted.
Added:
llvm/trunk/test/Transforms/LoopSimplify/ashr-crash.ll
llvm/trunk/test/Transforms/LoopSimplify/notify-scev.ll
Modified:
llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=198631&r1=198630&r2=198631&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Mon Jan 6 13:43:14 2014
@@ -784,6 +784,13 @@ namespace llvm {
/// disconnect it from a def-use chain linking it to a loop.
void forgetValue(Value *V);
+ /// \brief Called when the client has changed the disposition of values in
+ /// this loop.
+ ///
+ /// We don't have a way to invalidate per-loop dispositions. Clear and
+ /// recompute is simpler.
+ void forgetLoopDispositions(const Loop *L) { LoopDispositions.clear(); }
+
/// GetMinTrailingZeros - Determine the minimum number of zero bits that S
/// is guaranteed to end in (at every loop iteration). It is, at the same
/// time, the minimum number of times S is divisible by 2. For example,
Modified: llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp?rev=198631&r1=198630&r2=198631&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LoopSimplify.cpp Mon Jan 6 13:43:14 2014
@@ -309,6 +309,7 @@ ReprocessLoop:
// Attempt to hoist out all instructions except for the
// comparison and the branch.
bool AllInvariant = true;
+ bool AnyInvariant = false;
for (BasicBlock::iterator I = ExitingBlock->begin(); &*I != BI; ) {
Instruction *Inst = I++;
// Skip debug info intrinsics.
@@ -316,12 +317,19 @@ ReprocessLoop:
continue;
if (Inst == CI)
continue;
- if (!L->makeLoopInvariant(Inst, Changed,
- Preheader ? Preheader->getTerminator() : 0)) {
+ if (!L->makeLoopInvariant(Inst, AnyInvariant,
+ Preheader ? Preheader->getTerminator() : 0)) {
AllInvariant = false;
break;
}
}
+ if (AnyInvariant) {
+ Changed = true;
+ // The loop disposition of all SCEV expressions that depend on any
+ // hoisted values have also changed.
+ if (SE)
+ SE->forgetLoopDispositions(L);
+ }
if (!AllInvariant) continue;
// The block has now been cleared of all instructions except for
@@ -334,11 +342,10 @@ ReprocessLoop:
DEBUG(dbgs() << "LoopSimplify: Eliminating exiting block "
<< ExitingBlock->getName() << "\n");
- // If any reachable control flow within this loop has changed, notify
- // ScalarEvolution. Currently assume the parent loop doesn't change
- // (spliting edges doesn't count). If blocks, CFG edges, or other values
- // in the parent loop change, then we need call to forgetLoop() for the
- // parent instead.
+ // Notify ScalarEvolution before deleting this block. Currently assume the
+ // parent loop doesn't change (spliting edges doesn't count). If blocks,
+ // CFG edges, or other values in the parent loop change, then we need call
+ // to forgetLoop() for the parent instead.
if (SE)
SE->forgetLoop(L);
Added: llvm/trunk/test/Transforms/LoopSimplify/ashr-crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopSimplify/ashr-crash.ll?rev=198631&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopSimplify/ashr-crash.ll (added)
+++ llvm/trunk/test/Transforms/LoopSimplify/ashr-crash.ll Mon Jan 6 13:43:14 2014
@@ -0,0 +1,80 @@
+; RUN: opt -basicaa -loop-rotate -licm -instcombine -indvars -loop-unroll -S %s | FileCheck %s
+;
+; PR18361: ScalarEvolution::getAddRecExpr():
+; Assertion `isLoopInvariant(Operands[i],...
+;
+; After a series of loop optimizations, SCEV's LoopDispositions grow stale.
+; In particular, LoopSimplify hoists %cmp4, resulting in this SCEV for %add:
+; {(zext i1 %cmp4 to i32),+,1}<nw><%for.cond1.preheader>
+;
+; When recomputing the SCEV for %ashr, we truncate the operands to get:
+; (zext i1 %cmp4 to i16)
+;
+; This SCEV was never mapped to a value so never invalidated. It's
+; loop disposition is still marked as non-loop-invariant, which is
+; inconsistent with the AddRec.
+
+target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+ at d = common global i32 0, align 4
+ at a = common global i32 0, align 4
+ at c = common global i32 0, align 4
+ at b = common global i32 0, align 4
+
+; Check that the def-use chain that leads to the bad SCEV is still
+; there, and part of it is hoisted to the entry block.
+;
+; CHECK-LABEL: @foo
+; CHECK-LABEL: entry:
+; CHECK: %cmp4
+; CHECK-LABEL: for.cond1.preheader:
+; CHECK-LABEL: for.body3:
+; CHECK: %1 = zext i1 %cmp4 to i32
+; CHECK: %xor = xor i32 %1, 1
+define void @foo() {
+entry:
+ br label %for.cond
+
+for.cond: ; preds = %for.inc7, %entry
+ %storemerge = phi i32 [ 0, %entry ], [ %inc8, %for.inc7 ]
+ %f.0 = phi i32 [ undef, %entry ], [ %f.1, %for.inc7 ]
+ store i32 %storemerge, i32* @d, align 4
+ %cmp = icmp slt i32 %storemerge, 1
+ br i1 %cmp, label %for.cond1, label %for.end9
+
+for.cond1: ; preds = %for.cond, %for.body3
+ %storemerge1 = phi i32 [ %inc, %for.body3 ], [ 0, %for.cond ]
+ %f.1 = phi i32 [ %xor, %for.body3 ], [ %f.0, %for.cond ]
+ store i32 %storemerge1, i32* @a, align 4
+ %cmp2 = icmp slt i32 %storemerge1, 1
+ br i1 %cmp2, label %for.body3, label %for.inc7
+
+for.body3: ; preds = %for.cond1
+ %0 = load i32* @c, align 4
+ %cmp4 = icmp sge i32 %storemerge1, %0
+ %conv = zext i1 %cmp4 to i32
+ %1 = load i32* @d, align 4
+ %add = add nsw i32 %conv, %1
+ %sext = shl i32 %add, 16
+ %conv6 = ashr exact i32 %sext, 16
+ %xor = xor i32 %conv6, 1
+ %inc = add nsw i32 %storemerge1, 1
+ br label %for.cond1
+
+for.inc7: ; preds = %for.cond1
+ %2 = load i32* @d, align 4
+ %inc8 = add nsw i32 %2, 1
+ br label %for.cond
+
+for.end9: ; preds = %for.cond
+ %cmp10 = icmp sgt i32 %f.0, 0
+ br i1 %cmp10, label %if.then, label %if.end
+
+if.then: ; preds = %for.end9
+ store i32 0, i32* @b, align 4
+ br label %if.end
+
+if.end: ; preds = %if.then, %for.end9
+ ret void
+}
Added: llvm/trunk/test/Transforms/LoopSimplify/notify-scev.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopSimplify/notify-scev.ll?rev=198631&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/LoopSimplify/notify-scev.ll (added)
+++ llvm/trunk/test/Transforms/LoopSimplify/notify-scev.ll Mon Jan 6 13:43:14 2014
@@ -0,0 +1,110 @@
+; RUN: opt -indvars -S %s | FileCheck %s
+;
+; PR18384: ValueHandleBase::ValueIsDeleted.
+;
+; Ensure that LoopSimplify calls ScalarEvolution::forgetLoop before
+; deleting a block, regardless of whether any values were hoisted out
+; of the block.
+
+target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-darwin"
+
+%struct.Params = type { [2 x [4 x [16 x i16]]] }
+
+; Verify that the loop tail is deleted, and we don't crash!
+;
+; CHECK-LABEL: @t
+; CHECK-LABEL: for.cond127.preheader:
+; CHECK-NOT: for.cond127:
+; CHECK-LABEL: for.body129:
+define void @t() {
+entry:
+ br label %for.body102
+
+for.body102:
+ br i1 undef, label %for.cond127.preheader, label %for.inc203
+
+for.cond127.preheader:
+ br label %for.body129
+
+for.cond127:
+ %cmp128 = icmp slt i32 %inc191, 2
+ br i1 %cmp128, label %for.body129, label %for.end192
+
+for.body129:
+ %uv.013 = phi i32 [ 0, %for.cond127.preheader ], [ %inc191, %for.cond127 ]
+ %idxprom130 = sext i32 %uv.013 to i64
+ br i1 undef, label %for.cond135.preheader.lr.ph, label %for.end185
+
+for.cond135.preheader.lr.ph:
+ br i1 undef, label %for.cond135.preheader.lr.ph.split.us, label %for.cond135.preheader.lr.ph.split_crit_edge
+
+for.cond135.preheader.lr.ph.split_crit_edge:
+ br label %for.cond135.preheader.lr.ph.split
+
+for.cond135.preheader.lr.ph.split.us:
+ br label %for.cond135.preheader.us
+
+for.cond135.preheader.us:
+ %block_y.09.us = phi i32 [ 0, %for.cond135.preheader.lr.ph.split.us ], [ %add184.us, %for.cond132.us ]
+ br i1 true, label %for.cond138.preheader.lr.ph.us, label %for.end178.us
+
+for.end178.us:
+ %add184.us = add nsw i32 %block_y.09.us, 4
+ br i1 undef, label %for.end185split.us-lcssa.us, label %for.cond132.us
+
+for.end174.us:
+ br i1 undef, label %for.cond138.preheader.us, label %for.cond135.for.end178_crit_edge.us
+
+for.inc172.us:
+ br i1 undef, label %for.cond142.preheader.us, label %for.end174.us
+
+for.body145.us:
+ %arrayidx163.us = getelementptr inbounds %struct.Params* undef, i64 0, i32 0, i64 %idxprom130, i64 %idxprom146.us
+ br i1 undef, label %for.body145.us, label %for.inc172.us
+
+for.cond142.preheader.us:
+ %j.04.us = phi i32 [ %block_y.09.us, %for.cond138.preheader.us ], [ undef, %for.inc172.us ]
+ %idxprom146.us = sext i32 %j.04.us to i64
+ br label %for.body145.us
+
+for.cond138.preheader.us:
+ br label %for.cond142.preheader.us
+
+for.cond132.us:
+ br i1 undef, label %for.cond135.preheader.us, label %for.cond132.for.end185_crit_edge.us-lcssa.us
+
+for.cond138.preheader.lr.ph.us:
+ br label %for.cond138.preheader.us
+
+for.cond135.for.end178_crit_edge.us:
+ br label %for.end178.us
+
+for.end185split.us-lcssa.us:
+ br label %for.end185split
+
+for.cond132.for.end185_crit_edge.us-lcssa.us:
+ br label %for.cond132.for.end185_crit_edge
+
+for.cond135.preheader.lr.ph.split:
+ br label %for.end185split
+
+for.end185split:
+ br label %for.end185
+
+for.cond132.for.end185_crit_edge:
+ br label %for.end185
+
+for.end185:
+ %inc191 = add nsw i32 %uv.013, 1
+ br i1 false, label %for.end192, label %for.cond127
+
+for.end192:
+ br label %for.inc203
+
+for.inc203:
+ br label %for.end205
+
+for.end205:
+ ret void
+}
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