diff options
Diffstat (limited to 'llvm/test/Transforms/BDCE/invalidate-assumptions.ll')
| -rw-r--r-- | llvm/test/Transforms/BDCE/invalidate-assumptions.ll | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/llvm/test/Transforms/BDCE/invalidate-assumptions.ll b/llvm/test/Transforms/BDCE/invalidate-assumptions.ll index ac337c44ada..094c5ec6bd9 100644 --- a/llvm/test/Transforms/BDCE/invalidate-assumptions.ll +++ b/llvm/test/Transforms/BDCE/invalidate-assumptions.ll @@ -1,6 +1,6 @@ ; RUN: opt -bdce %s -S | FileCheck %s -; FIXME: The 'nuw' on the subtract allows us to deduce that %setbit is not demanded. +; The 'nuw' on the subtract allows us to deduce that %setbit is not demanded. ; But if we change that value to '0', then the 'nuw' is no longer valid. If we don't ; remove the 'nuw', another pass (-instcombine) may make a transform based on an ; that incorrect assumption and we can miscompile: @@ -11,7 +11,7 @@ define i1 @PR33695(i1 %b, i8 %x) { ; CHECK-NEXT: [[SETBIT:%.*]] = or i8 %x, 64 ; CHECK-NEXT: [[LITTLE_NUMBER:%.*]] = zext i1 %b to i8 ; CHECK-NEXT: [[BIG_NUMBER:%.*]] = shl i8 0, 1 -; CHECK-NEXT: [[SUB:%.*]] = sub nuw i8 [[BIG_NUMBER]], [[LITTLE_NUMBER]] +; CHECK-NEXT: [[SUB:%.*]] = sub i8 [[BIG_NUMBER]], [[LITTLE_NUMBER]] ; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[SUB]] to i1 ; CHECK-NEXT: ret i1 [[TRUNC]] ; @@ -23,7 +23,7 @@ define i1 @PR33695(i1 %b, i8 %x) { ret i1 %trunc } -; FIXME: Similar to above, but now with more no-wrap. +; Similar to above, but now with more no-wrap. ; https://bugs.llvm.org/show_bug.cgi?id=34037 define i64 @PR34037(i64 %m, i32 %r, i64 %j, i1 %b, i32 %k, i64 %p) { @@ -34,9 +34,9 @@ define i64 @PR34037(i64 %m, i32 %r, i64 %j, i1 %b, i32 %k, i64 %p) { ; CHECK-NEXT: [[OR:%.*]] = or i64 %j, 0 ; CHECK-NEXT: [[SHL:%.*]] = shl i64 0, 29 ; CHECK-NEXT: [[CONV1:%.*]] = select i1 %b, i64 7, i64 0 -; CHECK-NEXT: [[SUB:%.*]] = sub nuw nsw i64 [[SHL]], [[CONV1]] +; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[SHL]], [[CONV1]] ; CHECK-NEXT: [[CONV2:%.*]] = zext i32 %k to i64 -; CHECK-NEXT: [[MUL:%.*]] = mul nsw i64 [[SUB]], [[CONV2]] +; CHECK-NEXT: [[MUL:%.*]] = mul i64 [[SUB]], [[CONV2]] ; CHECK-NEXT: [[CONV4:%.*]] = and i64 %p, 65535 ; CHECK-NEXT: [[AND5:%.*]] = and i64 [[MUL]], [[CONV4]] ; CHECK-NEXT: ret i64 [[AND5]] @@ -55,3 +55,32 @@ define i64 @PR34037(i64 %m, i32 %r, i64 %j, i1 %b, i32 %k, i64 %p) { ret i64 %and5 } +; This is a manufactured example based on the 1st test to prove that the +; assumption-killing algorithm stops at the call. Ie, it does not remove +; nsw/nuw from the 'add' because a call demands all bits of its argument. + +declare i1 @foo(i1) + +define i1 @poison_on_call_user_is_ok(i1 %b, i8 %x) { +; CHECK-LABEL: @poison_on_call_user_is_ok( +; CHECK-NEXT: [[SETBIT:%.*]] = or i8 %x, 64 +; CHECK-NEXT: [[LITTLE_NUMBER:%.*]] = zext i1 %b to i8 +; CHECK-NEXT: [[BIG_NUMBER:%.*]] = shl i8 0, 1 +; CHECK-NEXT: [[SUB:%.*]] = sub i8 [[BIG_NUMBER]], [[LITTLE_NUMBER]] +; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[SUB]] to i1 +; CHECK-NEXT: [[CALL_RESULT:%.*]] = call i1 @foo(i1 [[TRUNC]]) +; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i1 [[CALL_RESULT]], true +; CHECK-NEXT: [[MUL:%.*]] = mul i1 [[TRUNC]], [[ADD]] +; CHECK-NEXT: ret i1 [[MUL]] +; + %setbit = or i8 %x, 64 + %little_number = zext i1 %b to i8 + %big_number = shl i8 %setbit, 1 + %sub = sub nuw i8 %big_number, %little_number + %trunc = trunc i8 %sub to i1 + %call_result = call i1 @foo(i1 %trunc) + %add = add nsw nuw i1 %call_result, 1 + %mul = mul i1 %trunc, %add + ret i1 %mul +} + |
