Hi,
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80158 reports an ICE in
SLSR while building 416.gamess on x86_64. This is a latent (but
previously harmless) bug that was exposed by the fix for PR80054.
When replacing any statement with a strength reduction, SLSR updates
the candidate statement S associated with the associated candidate
record in the candidate table. However, S may actually be associated
with two candidate records when an expression may be treated as
either a CAND_ADD or a CAND_MULT. In this case, the second one can
be reached via the next_interp field.
In the excerpt from 416.gamess, the first candidate record was
updated when its statement was replaced, but the next-interp record
was not. Later, that record was used as a basis for another tree
of strength-reduction candidates, but since it now pointed to an
orphaned statement without a basic block, the ICE occurred when
checking dominance against the statement's block.
The fix is simply to ensure that the next_interp record is always
updated when present.
I've bootstrapped and tested this on powerpc64le-unknown-linux-gnu
with no regressions. I tested that the standalone test works on
x86_64 with this fix, but I have been unable to perform an x86_64
regstrap because the machine I have access to has insufficient
disk space. :/ I would appreciate it if you could do this for me.
Assuming no problems with x86_64 regstrap, is this ok for trunk?
Note: I will be unreachable from now until next Tuesday (i.e.,
returning the 28th). If needed, please feel free to commit the
patch on my behalf. Otherwise I will attend to it when I return.
Thanks!
Bill
[gcc]
2017-03-23 Bill Schmidt <wschm...@linux.vnet.ibm.com>
PR tree-optimization/80158
* gimple-ssa-strength-reduction.c (replace_mult_candidate): When
replacing a candidate statement, also replace it for the
candidate's alternate interpretation.
(replace_rhs_if_not_dup): Likewise.
(replace_one_candidate): Likewise.
[gcc/testsuite]
2017-03-23 Bill Schmidt <wschm...@linux.vnet.ibm.com>
PR tree-optimization/80158
* gfortran.fortran-torture/compile/pr80158.f: New file.
Index: gcc/gimple-ssa-strength-reduction.c
===================================================================
--- gcc/gimple-ssa-strength-reduction.c (revision 246420)
+++ gcc/gimple-ssa-strength-reduction.c (working copy)
@@ -2089,6 +2089,8 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
gsi_replace (&gsi, copy_stmt, false);
c->cand_stmt = copy_stmt;
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = copy_stmt;
if (dump_file && (dump_flags & TDF_DETAILS))
stmt_to_print = copy_stmt;
}
@@ -2118,6 +2120,8 @@ replace_mult_candidate (slsr_cand_t c, tree basis_
basis_name, bump_tree);
update_stmt (gsi_stmt (gsi));
c->cand_stmt = gsi_stmt (gsi);
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
if (dump_file && (dump_flags & TDF_DETAILS))
stmt_to_print = gsi_stmt (gsi);
}
@@ -3405,6 +3409,8 @@ replace_rhs_if_not_dup (enum tree_code new_code, t
gimple_assign_set_rhs_with_ops (&gsi, new_code, new_rhs1, new_rhs2);
update_stmt (gsi_stmt (gsi));
c->cand_stmt = gsi_stmt (gsi);
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
if (dump_file && (dump_flags & TDF_DETAILS))
return gsi_stmt (gsi);
@@ -3511,6 +3517,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
gimple_assign_set_rhs_with_ops (&gsi, MINUS_EXPR, basis_name, rhs2);
update_stmt (gsi_stmt (gsi));
c->cand_stmt = gsi_stmt (gsi);
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = gsi_stmt (gsi);
if (dump_file && (dump_flags & TDF_DETAILS))
stmt_to_print = gsi_stmt (gsi);
@@ -3532,6 +3540,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
gimple_set_location (copy_stmt, gimple_location (c->cand_stmt));
gsi_replace (&gsi, copy_stmt, false);
c->cand_stmt = copy_stmt;
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = copy_stmt;
if (dump_file && (dump_flags & TDF_DETAILS))
stmt_to_print = copy_stmt;
@@ -3543,6 +3553,8 @@ replace_one_candidate (slsr_cand_t c, unsigned i,
gimple_set_location (cast_stmt, gimple_location (c->cand_stmt));
gsi_replace (&gsi, cast_stmt, false);
c->cand_stmt = cast_stmt;
+ if (c->next_interp)
+ lookup_cand (c->next_interp)->cand_stmt = cast_stmt;
if (dump_file && (dump_flags & TDF_DETAILS))
stmt_to_print = cast_stmt;
Index: gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f
===================================================================
--- gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f (nonexistent)
+++ gcc/testsuite/gfortran.fortran-torture/compile/pr80158.f (working copy)
@@ -0,0 +1,16 @@
+ SUBROUTINE DRPAUL(SMAT,TMAT,EPS,EPT,SIJ,TIJ,WRK,VEC,ARRAY,FMO,
+ * XMKVIR,TMJ,XMI,YMI,ZMI,ZQQ,L1,L1EF,LNA,LNA2,
+ * NAEF,L2,NLOC,NVIR,PROVEC,FOCKMA,MXBF,MXMO2)
+ DIMENSION CMO(L1,L1),TLOC(LNA,LNA),SMJ(L1,NAEF),XMK(L1,LNA)
+ DO I = 1,LNA
+ DO J = 1,LNA
+ IF (I.LE.NOUT) TLOC(I,J) = ZERO
+ IF (J.LE.NOUT) TLOC(I,J) = ZERO
+ END DO
+ DO NA=1,NOC
+ IF ( ABS(E(NI)-E(NA)) .GE.TOL) THEN
+ END IF
+ END DO
+ END DO
+ END
+
