[polly] r278738 - [ScopDetect] Do not assert in case of AddRecs with non-constant start expression

[Michael Kruse via llvm-commits]

Is this related to llvm.org/PR28871 ?

Michael

2016-08-15 22:59 GMT+02:00 Tobias Grosser via llvm-commits
<llvm-commits at lists.llvm.org>:
> Author: grosser
> Date: Mon Aug 15 15:59:30 2016
> New Revision: 278738
>
> URL: http://llvm.org/viewvc/llvm-project?rev=278738&view=rev
> Log:
> [ScopDetect] Do not assert in case of AddRecs with non-constant start expression
>
> Added:
>     polly/trunk/test/ScopDetect/non-constant-add-rec-start-expr.ll
> Modified:
>     polly/trunk/lib/Support/SCEVValidator.cpp
>
> Modified: polly/trunk/lib/Support/SCEVValidator.cpp
> URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Support/SCEVValidator.cpp?rev=278738&r1=278737&r2=278738&view=diff
> ==============================================================================
> --- polly/trunk/lib/Support/SCEVValidator.cpp (original)
> +++ polly/trunk/lib/Support/SCEVValidator.cpp Mon Aug 15 15:59:30 2016
> @@ -232,8 +232,7 @@ public:
>        return ValidatorResult(SCEVType::INVALID);
>      }
>
> -    assert(Start.isConstant() && Recurrence.isConstant() &&
> -           "Expected 'Start' and 'Recurrence' to be constant");
> +    assert(Recurrence.isConstant() && "Expected 'Recurrence' to be constant");
>
>      // Directly generate ValidatorResult for Expr if 'start' is zero.
>      if (Expr->getStart()->isZero())
>
> Added: polly/trunk/test/ScopDetect/non-constant-add-rec-start-expr.ll
> URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopDetect/non-constant-add-rec-start-expr.ll?rev=278738&view=auto
> ==============================================================================
> --- polly/trunk/test/ScopDetect/non-constant-add-rec-start-expr.ll (added)
> +++ polly/trunk/test/ScopDetect/non-constant-add-rec-start-expr.ll Mon Aug 15 15:59:30 2016
> @@ -0,0 +1,50 @@
> +; RUN: opt %loadPolly -polly-detect -\
> +; RUN:     -analyze < %s | FileCheck %s
> +
> +; CHECK: Valid Region for Scop: bb11 => bb25
> +
> +; Ensure that this test case does not trigger an assertion. At some point,
> +; we asserted on scops containing accesses where the access function contained
> +; an AddRec expression with a non-constant step expression. This got missed, as
> +; this very specific pattern does not seem too common. Even in this test case,
> +; it disappears as soon as we turn the infinite loop into a finite loop.
> +
> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-unknown-linux-gnu"
> +
> +define void @hoge() local_unnamed_addr {
> +bb:
> +  %tmp = alloca [18 x [16 x i32]]
> +  %tmp1 = alloca [17 x i32]
> +  br label %bb2
> +
> +bb2:
> +  %tmp3 = phi i64 [ 0, %bb ], [ %tmp5, %bb2 ]
> +  %tmp4 = add nuw nsw i64 %tmp3, 2
> +  %tmp5 = add nuw nsw i64 %tmp3, 1
> +  br i1 undef, label %bb2, label %bb11
> +
> +bb11:
> +  %tmp12 = phi i64 [ %tmp23, %bb24 ], [ 1, %bb2 ]
> +  %tmp14 = getelementptr inbounds [17 x i32], [17 x i32]* %tmp1, i64 0, i64 1
> +  br label %bb15
> +
> +bb15:
> +  %tmp16 = sub nsw i64 %tmp12, 1
> +  %tmp17 = shl i64 %tmp16, 32
> +  %tmp18 = ashr exact i64 %tmp17, 32
> +  %tmp19 = getelementptr inbounds [18 x [16 x i32]], [18 x [16 x i32]]* %tmp, i64 0, i64 %tmp4, i64 %tmp18
> +  %tmp20 = load i32, i32* %tmp19, align 4
> +  store i32 4, i32* %tmp19
> +  br label %bb21
> +
> +bb21:
> +  %tmp23 = add nuw nsw i64 %tmp12, 1
> +  br i1 true, label %bb24, label %bb25
> +
> +bb24:
> +  br label %bb11
> +
> +bb25:
> +  ret void
> +}
>
>
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