| Message ID | DB5PR0801MB2742078DDAB430C77EB39C67E7160@DB5PR0801MB2742.eurprd08.prod.outlook.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PR83695] Fix ICE by resetting cached scev info after interchange. | expand |
On Thu, Jan 11, 2018 at 1:49 PM, Bin Cheng <Bin.Cheng@arm.com> wrote: > Hi, > As explained in comment of PR83695, outdated cached scev info could be referred > by later interchange of outer loops in nest. This simple patch fixes ICE by > resetting cached scev info after interchange. It's expensive resetting all scev > information but might not be a problem here given we only interchange in limited > cases. > > Bootstrap and test on x86_64 and AArch64. Is it OK? Ok. Richard. > Thanks, > bin > > 2018-01-11 Bin Cheng <bin.cheng@arm.com> > > PR tree-optimization/83695 > * gimple-loop-linterchange.cc > (tree_loop_interchange::interchange_loops): Call scev_reset_htab to > reset cached scev information after interchange. > (pass_linterchange::execute): Remove call to scev_reset_htab. > > gcc/testsuite > 2018-01-11 Bin Cheng <bin.cheng@arm.com> > > PR tree-optimization/83695 > * gcc.dg/tree-ssa/pr83695.c: New test.
diff --git a/gcc/gimple-loop-interchange.cc b/gcc/gimple-loop-interchange.cc index 01a26c0..eb35263 100644 --- a/gcc/gimple-loop-interchange.cc +++ b/gcc/gimple-loop-interchange.cc @@ -1119,6 +1119,10 @@ tree_loop_interchange::interchange_loops (loop_cand &iloop, loop_cand &oloop) oloop.m_loop->any_likely_upper_bound = false; free_numbers_of_iterations_estimates (oloop.m_loop); + /* Clear all cached scev information. This is expensive but shouldn't be + a problem given we interchange in very limited times. */ + scev_reset_htab (); + /* ??? The association between the loop data structure and the CFG changed, so what was loop N at the source level is now loop M. We should think of retaining the association or breaking @@ -2070,9 +2074,6 @@ pass_linterchange::execute (function *fun) loop_nest.release (); } - if (changed_p) - scev_reset_htab (); - return changed_p ? (TODO_update_ssa_only_virtuals) : 0; } diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr83695.c b/gcc/testsuite/gcc.dg/tree-ssa/pr83695.c new file mode 100644 index 0000000..af56a31 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr83695.c @@ -0,0 +1,23 @@ +/* { dg-do compile } */ +/* { dg-options "-O3" } */ + +int a[3][3][3], b, d; +short c; +unsigned char e; + +static void f () +{ + for (c = 0; c < 2; c++) + for (e = 0; e < 3; e++) + for (b = 0; b < 3; b++) + a[b][e][b] = 0; + while (1) + ; +} + +int main () +{ + if (d) + f (); + return 0; +}