1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2025-01-31 20:51:52 +01:00
llvm-mirror/test/Analysis/ScalarEvolution/exact-exit-count-more-precise.ll
Florian Hahn 961b7ba244 [SCEV] Handle case where MaxBECount is less precise than ExactBECount for OR.
In some cases, MaxBECount can be less precise than ExactBECount for AND
and OR (the AND case was PR26207). In the OR test case, both ExactBECounts are
undef, but MaxBECount are different, so we hit the assertion below. This
patch uses the same solution the AND case already uses.

Assertion failed:
   ((isa<SCEVCouldNotCompute>(ExactNotTaken) || !isa<SCEVCouldNotCompute>(MaxNotTaken))
     && "Exact is not allowed to be less precise than Max"), function ExitLimit

This patch also consolidates test cases for both AND and OR in a single
test case.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13245

Reviewers: sanjoy, efriedma, mkazantsev

Reviewed By: sanjoy

Differential Revision: https://reviews.llvm.org/D58853

llvm-svn: 355259
2019-03-02 02:31:44 +00:00

50 lines
1.7 KiB
LLVM

; RUN: opt -analyze -scalar-evolution %s | FileCheck %s
target triple = "x86_64-unknown-linux-gnu"
define void @test_and(i16 %in) {
br label %bb2
bb2: ; preds = %bb1.i, %bb2, %0
%_tmp44.i = icmp slt i16 %in, 2
br i1 %_tmp44.i, label %bb1.i, label %bb2
bb1.i: ; preds = %bb1.i, %bb2
%_tmp25.i = phi i16 [ %in, %bb2 ], [ %_tmp6.i, %bb1.i ]
%_tmp6.i = add nsw i16 %_tmp25.i, 1
%_tmp10.i = icmp sge i16 %_tmp6.i, 2
%exitcond.i = icmp eq i16 %_tmp6.i, 2
%or.cond = and i1 %_tmp10.i, %exitcond.i
br i1 %or.cond, label %bb2, label %bb1.i
}
; CHECK-LABEL: Determining loop execution counts for: @test_and
; CHECK-NEXT: Loop %bb1.i: backedge-taken count is (1 + (-1 * %in))
; CHECK-NEXT: Loop %bb1.i: max backedge-taken count is -1
; CHECK-NEXT: Loop %bb1.i: Predicated backedge-taken count is (1 + (-1 * %in))
define void @test_or() {
%C10 = icmp slt i1 undef, undef
br i1 %C10, label %BB, label %exit
BB: ; preds = %BB, %0
%indvars.iv = phi i64 [ -1, %BB ], [ -1, %0 ]
%sum.01 = phi i32 [ %2, %BB ], [ undef, %0 ]
%1 = trunc i64 %indvars.iv to i32
%2 = add nsw i32 %1, %sum.01
%B3 = add i32 %1, %2
%C11 = icmp ult i32 %2, %1
%C5 = icmp sle i32 %1, %B3
%B = or i1 %C5, %C11
br i1 %B, label %BB, label %exit
exit: ; preds = %BB, %0
ret void
}
; CHECK-LABEL: Determining loop execution counts for: @test_or
; CHECK-NEXT: Loop %BB: backedge-taken count is undef
; CHECK-NEXT: Loop %BB: max backedge-taken count is -1
; CHECK-NEXT: Loop %BB: Predicated backedge-taken count is undef