diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/include/llvm/Analysis/ScalarEvolution.h | 7 | ||||
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopSimplify.cpp | 27 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopSimplify/ashr-crash.ll | 80 |
3 files changed, 10 insertions, 104 deletions
diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h index 26dd4dd5fcf..a397046315b 100644 --- a/llvm/include/llvm/Analysis/ScalarEvolution.h +++ b/llvm/include/llvm/Analysis/ScalarEvolution.h @@ -784,13 +784,6 @@ 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, diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp index 1927d288d43..6d5f16ca333 100644 --- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp +++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp @@ -309,7 +309,6 @@ 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. @@ -317,26 +316,12 @@ ReprocessLoop: continue; if (Inst == CI) continue; - if (!L->makeLoopInvariant(Inst, AnyInvariant, - Preheader ? Preheader->getTerminator() : 0)) { + if (!L->makeLoopInvariant(Inst, Changed, + Preheader ? Preheader->getTerminator() : 0)) { AllInvariant = false; break; } } - if (AnyInvariant) { - Changed = true; - // 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. - if (SE) { - SE->forgetLoop(L); - // The loop disposition of all SCEV expressions that depend on any - // hoisted values have also changed. - SE->forgetLoopDispositions(L); - } - } if (!AllInvariant) continue; // The block has now been cleared of all instructions except for @@ -349,6 +334,14 @@ 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. + if (SE) + SE->forgetLoop(L); + assert(pred_begin(ExitingBlock) == pred_end(ExitingBlock)); Changed = true; LI->removeBlock(ExitingBlock); diff --git a/llvm/test/Transforms/LoopSimplify/ashr-crash.ll b/llvm/test/Transforms/LoopSimplify/ashr-crash.ll deleted file mode 100644 index f736eefc9b3..00000000000 --- a/llvm/test/Transforms/LoopSimplify/ashr-crash.ll +++ /dev/null @@ -1,80 +0,0 @@ -; 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" - -@d = common global i32 0, align 4 -@a = common global i32 0, align 4 -@c = common global i32 0, align 4 -@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 -} |
