diff options
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 3 | ||||
| -rw-r--r-- | llvm/test/Analysis/ScalarEvolution/shift-op.ll | 19 |
2 files changed, 21 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 9bc8f2dc83d..8001d99603a 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -7074,6 +7074,7 @@ ScalarEvolution::computeExitLimitFromICmp(const Loop *L, Cond = ExitCond->getPredicate(); else Cond = ExitCond->getInversePredicate(); + const ICmpInst::Predicate OriginalCond = Cond; // Handle common loops like: for (X = "string"; *X; ++X) if (LoadInst *LI = dyn_cast<LoadInst>(ExitCond->getOperand(0))) @@ -7157,7 +7158,7 @@ ScalarEvolution::computeExitLimitFromICmp(const Loop *L, return ExhaustiveCount; return computeShiftCompareExitLimit(ExitCond->getOperand(0), - ExitCond->getOperand(1), L, Cond); + ExitCond->getOperand(1), L, OriginalCond); } ScalarEvolution::ExitLimit diff --git a/llvm/test/Analysis/ScalarEvolution/shift-op.ll b/llvm/test/Analysis/ScalarEvolution/shift-op.ll index fe832d56768..ae13b2879df 100644 --- a/llvm/test/Analysis/ScalarEvolution/shift-op.ll +++ b/llvm/test/Analysis/ScalarEvolution/shift-op.ll @@ -160,5 +160,24 @@ define void @test8(i32 %init) { ret void } +define void @test9() { +; CHECK-LABEL: Determining loop execution counts for: @test9 +; CHECK: Loop %loop: Unpredictable max backedge-taken count. + +; This is an infinite loop, make sure that it recognized as such. + +entry: + br label %loop + +leave: + ret void + +loop: + %iv = phi i32 [ -20, %entry ], [ %iv.shift, %loop ] + %iv.shift = ashr i32 %iv, 1 + %exit.cond = icmp sgt i32 %iv, -1 + br i1 %exit.cond, label %leave, label %loop +} + !0 = !{i32 0, i32 50000} !1 = !{i32 -5000, i32 -1} |
