Module: Mesa Branch: master Commit: 6fb685fe4b762c8030f86895707516e2481e9ece URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=6fb685fe4b762c8030f86895707516e2481e9ece
Author: Jason Ekstrand <[email protected]> Date: Fri Jul 12 11:01:40 2019 -0500 nir/regs_to_ssa: Handle regs in phi sources properly Sources of phi instructions act as if they occur at the very end of the predecessor block not the block in which the phi lives. In order to handle them correctly, we have to skip phi sources on the normal instruction walk and handle them as a separate walk over the successor phis. While registers in phi instructions is a bit of an oddity it can happen when we temporarily go out-of-SSA for control-flow manipulations. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111075 Cc: [email protected] Reviewed-by: Caio Marcelo de Oliveira Filho <[email protected]> --- src/compiler/nir/nir_lower_regs_to_ssa.c | 34 ++++++++++++++++++++++++++++++-- 1 file changed, 32 insertions(+), 2 deletions(-) diff --git a/src/compiler/nir/nir_lower_regs_to_ssa.c b/src/compiler/nir/nir_lower_regs_to_ssa.c index 0db11ff1d1c..76ed1287379 100644 --- a/src/compiler/nir/nir_lower_regs_to_ssa.c +++ b/src/compiler/nir/nir_lower_regs_to_ssa.c @@ -251,9 +251,17 @@ nir_lower_regs_to_ssa_impl(nir_function_impl *impl) nir_foreach_block(block, impl) { nir_foreach_instr(instr, block) { - if (instr->type == nir_instr_type_alu) { + switch (instr->type) { + case nir_instr_type_alu: rewrite_alu_instr(nir_instr_as_alu(instr), &state); - } else { + break; + + case nir_instr_type_phi: + /* We rewrite sources as a separate pass */ + nir_foreach_dest(instr, rewrite_dest, &state); + break; + + default: nir_foreach_src(instr, rewrite_src, &state); nir_foreach_dest(instr, rewrite_dest, &state); } @@ -262,6 +270,28 @@ nir_lower_regs_to_ssa_impl(nir_function_impl *impl) nir_if *following_if = nir_block_get_following_if(block); if (following_if) rewrite_if_condition(following_if, &state); + + /* Handle phi sources that source from this block. We have to do this + * as a separate pass because the phi builder assumes that uses and + * defs are processed in an order that respects dominance. When we have + * loops, a phi source may be a back-edge so we have to handle it as if + * it were one of the last instructions in the predecessor block. + */ + for (unsigned i = 0; i < ARRAY_SIZE(block->successors); i++) { + if (block->successors[i] == NULL) + continue; + + nir_foreach_instr(instr, block->successors[i]) { + if (instr->type != nir_instr_type_phi) + break; + + nir_phi_instr *phi = nir_instr_as_phi(instr); + nir_foreach_phi_src(phi_src, phi) { + if (phi_src->pred == block) + rewrite_src(&phi_src->src, &state); + } + } + } } nir_phi_builder_finish(phi_build); _______________________________________________ mesa-commit mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-commit
