Hi! The following testcase ICEs (and only without -g), because we don't replace one VEC_COND_EXPR with .VCOND* call. We don't do that because gimple_expand_vec_set_expr adds some stmts before *gsi and then uses gsi_remove to remove it. gsi_remove moves the iterator to the next stmt and in the caller we then do gsi_next before looking at another stmt, which means we can skip processing of one stmt, which in this case happened to be a VEC_COND_EXPR but with -g is some debug stmt in between. As we always emit some stmts before it, it is easy to update the iterator to the last stmt emitted there, so that caller continues really with the next stmt.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2022-05-10 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/105528 * gimple-isel.cc (gimple_expand_vec_set_expr): After gsi_remove set *gsi to gsi_for_stmt (ass_stmt). Fix up function comment. * gcc.dg/pr105528.c: New test. --- gcc/gimple-isel.cc.jj 2022-05-09 09:09:20.386472253 +0200 +++ gcc/gimple-isel.cc 2022-05-09 11:28:27.295925124 +0200 @@ -43,7 +43,7 @@ along with GCC; see the file COPYING3. /* Expand all ARRAY_REF(VIEW_CONVERT_EXPR) gimple assignments into calls to internal function based on vector type of selected expansion. i.e.: - VIEW_CONVERT_EXPR<int[4]>(u)[_1] = = i_4(D); + VIEW_CONVERT_EXPR<int[4]>(u)[_1] = i_4(D); => _7 = u; _8 = .VEC_SET (_7, i_4(D), _1); @@ -104,6 +104,7 @@ gimple_expand_vec_set_expr (struct funct if (gsi_remove (gsi, true) && gimple_purge_dead_eh_edges (bb)) cfg_changed = true; + *gsi = gsi_for_stmt (ass_stmt); } } --- gcc/testsuite/gcc.dg/pr105528.c.jj 2022-05-09 11:30:09.476529621 +0200 +++ gcc/testsuite/gcc.dg/pr105528.c 2022-05-09 11:30:35.091179163 +0200 @@ -0,0 +1,23 @@ +/* PR tree-optimization/105528 */ +/* { dg-do compile } */ +/* { dg-options "-O2 -Wno-psabi -fcompare-debug" } */ +/* { dg-additional-options "-mavx512f" { target i?86-*-* x86_64-*-* } } */ + +typedef unsigned V __attribute__((__vector_size__ (64))); +V g; + +V +bar (V v) +{ + V w; + v <<= (V){(V){}[53]} >= v & 5; + w[w[5]] -= ~0; + v %= ~0; + return v + w; +} + +void +foo (void) +{ + g -= (V){bar((V){~0})[3]}; +} Jakub