The testcase in this PR causes gcc to abort with
internal compiler error: Maximum number of LRA constraint passes is
achieved (30)
[in theory - I've not managed to reproduce this on my system with any
compiler]
The abort is premature, allowing LRA to continue would allow the
testcase to compile. Vlad would like to leave the check in, however, as
it is a good way to catch problems with machine descriptions as they are
converted to use LRA.
The following is a compromise I came up with after some internal
discussion. The idea is to leave the assert in under -fchecking, so that
release compilers do not prematurely abort for valid testcases, while
development builds get an additional sanity check.
Bootstrapped and tested on x86_64-linux. Ok?
Bernd
PR rtl-optimization/57676
* lra-assigns.c (lra_assign): Guard test for maximum iterations
with flag_checking.
PR rtl-optimization/57676
* gcc.dg/torture/pr57676.c: New test.
Index: gcc/lra-assigns.c
===================================================================
--- gcc/lra-assigns.c (revision 233451)
+++ gcc/lra-assigns.c (working copy)
@@ -1620,7 +1620,12 @@ lra_assign (void)
timevar_pop (TV_LRA_ASSIGN);
if (former_reload_pseudo_spill_p)
lra_assignment_iter_after_spill++;
- if (lra_assignment_iter_after_spill > LRA_MAX_ASSIGNMENT_ITERATION_NUMBER)
+ /* This is conditional on flag_checking because valid code can take
+ more than this maximum number of iteration, but at the same time
+ the test can uncover errors in machine descriptions. */
+ if (flag_checking
+ && (lra_assignment_iter_after_spill
+ > LRA_MAX_ASSIGNMENT_ITERATION_NUMBER))
internal_error
("Maximum number of LRA assignment passes is achieved (%d)\n",
LRA_MAX_ASSIGNMENT_ITERATION_NUMBER);
Index: gcc/testsuite/gcc.dg/torture/pr57676.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr57676.c (revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr57676.c (working copy)
@@ -0,0 +1,28 @@
+/* Verify that LRA does not abort prematurely in a release build of the
+ compiler. */
+/* { dg-do compile } */
+/* { dg-options "-fno-checking -w -funroll-loops" } */
+
+int a, b, c;
+
+void f(p1)
+{
+ for(;;)
+ {
+ if(p1 ? : (c /= 0))
+ {
+ int d;
+
+ for(; d; d++)
+ {
+ for(b = 0; b < 4; b++)
+ p1 /= p1;
+lbl:
+ while(a);
+ }
+ }
+
+ if((c &= 1))
+ goto lbl;
+ }
+}
