From 46d4dba6e64eb47dfa04beb8d9c623a29b3375df Mon Sep 17 00:00:00 2001 From: Nikita Popov Date: Sat, 1 Jun 2019 09:40:18 +0000 Subject: [IndVarSimplify] Fixup nowrap flags during LFTR (PR31181) Fix for https://bugs.llvm.org/show_bug.cgi?id=31181 and partial fix for LFTR poison handling issues in general. When LFTR moves a condition from pre-inc to post-inc, it may now depend on value that is poison due to nowrap flags. To avoid this, we clear any nowrap flag that SCEV cannot prove for the post-inc addrec. Additionally, LFTR may switch to a different IV that is dynamically dead and as such may be arbitrarily poison. This patch will correct nowrap flags in some but not all cases where this happens. This is related to the adoption of IR nowrap flags for the pre-inc addrec. (See some of the switch_to_different_iv tests, where flags are not dropped or insufficiently dropped.) Finally, there are likely similar issues with the handling of GEP inbounds, but we don't have a test case for this yet. Differential Revision: https://reviews.llvm.org/D60935 llvm-svn: 362292 --- llvm/test/Transforms/IndVarSimplify/lftr-pr31181.ll | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'llvm/test/Transforms') diff --git a/llvm/test/Transforms/IndVarSimplify/lftr-pr31181.ll b/llvm/test/Transforms/IndVarSimplify/lftr-pr31181.ll index 8316d8dbce2..6032b1d13ce 100644 --- a/llvm/test/Transforms/IndVarSimplify/lftr-pr31181.ll +++ b/llvm/test/Transforms/IndVarSimplify/lftr-pr31181.ll @@ -15,7 +15,7 @@ define i32 @test_drop_nuw() { ; CHECK: loop: ; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ -2, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] ; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a -; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[STOREMERGE]], 1 +; CHECK-NEXT: [[INC]] = add nsw i32 [[STOREMERGE]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 0 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] ; CHECK: exit: @@ -42,7 +42,7 @@ define i32 @test_drop_nsw() { ; CHECK: loop: ; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] ; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a -; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[STOREMERGE]], 1 +; CHECK-NEXT: [[INC]] = add nuw i32 [[STOREMERGE]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], -2147483648 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] ; CHECK: exit: @@ -155,7 +155,7 @@ define i32 @test_drop_nsw_var_lim(i32 %lim) { ; CHECK: loop: ; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ [[INC:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ] ; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a -; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[STOREMERGE]], 1 +; CHECK-NEXT: [[INC]] = add nuw i32 [[STOREMERGE]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], [[TMP0]] ; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT_LOOPEXIT:%.*]] ; CHECK: exit.loopexit: @@ -194,7 +194,7 @@ define i32 @switch_to_different_iv_post_inc(i32* %ptr, i1 %always_false) { ; CHECK-NEXT: br label [[ALWAYS_TAKEN]] ; CHECK: always_taken: ; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 -; CHECK-NEXT: [[IV2_INC]] = add nuw nsw i32 [[IV2]], 1 +; CHECK-NEXT: [[IV2_INC]] = add nuw i32 [[IV2]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2_INC]], -2147483627 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND]], label [[FOR_END:%.*]] ; CHECK: for.end: @@ -242,7 +242,7 @@ define i32 @switch_to_different_iv_pre_inc(i32* %ptr, i1 %always_false) { ; CHECK-NEXT: br label [[ALWAYS_TAKEN]] ; CHECK: always_taken: ; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 -; CHECK-NEXT: [[IV2_INC]] = add nuw nsw i32 [[IV2]], 1 +; CHECK-NEXT: [[IV2_INC]] = add nuw i32 [[IV2]], 1 ; CHECK-NEXT: br label [[FOR_COND]] ; CHECK: for.end: ; CHECK-NEXT: ret i32 0 @@ -329,7 +329,7 @@ define i32 @switch_to_different_iv_second_poison(i32* %ptr, i1 %always_false) { ; CHECK-NEXT: store volatile i32 [[IV2]], i32* [[PTR]] ; CHECK-NEXT: br label [[ALWAYS_TAKEN]] ; CHECK: always_taken: -; CHECK-NEXT: [[IV2_INC]] = add nuw nsw i32 [[IV2]], 1 +; CHECK-NEXT: [[IV2_INC]] = add nsw i32 [[IV2]], 1 ; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 ; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2_INC]], -2147483629 ; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND]], label [[FOR_END:%.*]] -- cgit v1.2.3