Mesa (main): nir/loop_analyze: skip unsupported induction variable early

[GitLab Mirror]

Module: Mesa
Branch: main
Commit: 3c93ebbae58e3e3f5b1ab716a801eb9dfb26fbff
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=3c93ebbae58e3e3f5b1ab716a801eb9dfb26fbff

Author: Qiang Yu <yuq825 at gmail.com>
Date:   Mon Jul 26 17:13:52 2021 +0800

nir/loop_analyze: skip unsupported induction variable early

Instead of fail in trip count calculation, just don't mark such
kind of variable as induction from the beginning.

Don't bother inline uniform to deal with such kind of variable
either.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Signed-off-by: Qiang Yu <yuq825 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11950>

---

 src/compiler/nir/nir_loop_analyze.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/compiler/nir/nir_loop_analyze.c b/src/compiler/nir/nir_loop_analyze.c
index 551680d11f5..65291a70a9a 100644
--- a/src/compiler/nir/nir_loop_analyze.c
+++ b/src/compiler/nir/nir_loop_analyze.c
@@ -416,6 +416,10 @@ compute_induction_information(loop_info_state *state)
             alu_src_var = src_var;
             nir_alu_instr *alu = nir_instr_as_alu(src_var->def->parent_instr);
 
+            /* Check for unsupported alu operations */
+            if (alu->op != nir_op_iadd && alu->op != nir_op_fadd)
+               break;
+
             if (nir_op_infos[alu->op].num_inputs == 2) {
                for (unsigned i = 0; i < 2; i++) {
                   /* Is one of the operands const or uniform, and the other the phi.
@@ -857,9 +861,8 @@ calculate_iterations(nir_const_value initial, nir_const_value step,
              induction_base_type);
    }
 
-   /* Check for nsupported alu operations */
-   if (alu->op != nir_op_iadd && alu->op != nir_op_fadd)
-      return -1;
+   /* Only variable with these update ops were marked as induction. */
+   assert(alu->op == nir_op_iadd || alu->op == nir_op_fadd);
 
    /* do-while loops can increment the starting value before the condition is
     * checked. e.g.