commit 0cbe0d2968cbea9f036857e3463b86a8a114b66c
author Rhys Perry <pendingchaos02@gmail.com> Wed Nov 15 19:14:50 2023 +0000
committer Marge Bot <emma+marge@anholt.net> Wed Dec 06 15:58:36 2023 +0000
tree bbeb558699b3fe3c8dbb2a3f31eaf41d8ca2d715
parent fc1ebc67b12978e1e580159560b69f8c7fb667a5

nir/loop_analyze: support loops with min/max and non-add incrementation

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26225>

src/compiler/nir/nir_loop_analyze.c

diff --git a/src/compiler/nir/nir_loop_analyze.c b/src/compiler/nir/nir_loop_analyze.c
index 8146070..293f83c 100644
--- a/src/compiler/nir/nir_loop_analyze.c
+++ b/src/compiler/nir/nir_loop_analyze.c
@@ -959,20 +959,23 @@
 static int32_t
 get_iteration_empirical(nir_scalar cond, nir_alu_instr *incr_alu,
                         nir_scalar basis, nir_const_value initial,
+                        nir_scalar limit_basis, nir_const_value limit,
                         bool invert_cond, unsigned execution_mode,
                         unsigned max_unroll_iterations)
 {
    int iter_count = 0;
    nir_const_value result;
-   nir_const_value iter = initial;
 
    const nir_scalar incr = nir_get_scalar(&incr_alu->def, basis.comp);
 
+   const nir_scalar original[] = {basis, limit_basis};
+   nir_const_value replacement[] = {initial, limit};
+
    while (iter_count <= max_unroll_iterations) {
       bool success;
 
-      success = try_eval_const_alu(&result, cond, &basis, &iter,
-                                   1, execution_mode);
+      success = try_eval_const_alu(&result, cond, original, replacement,
+                                   2, execution_mode);
       if (!success)
          return -1;
 
@@ -982,11 +985,11 @@
 
       iter_count++;
 
-      success = try_eval_const_alu(&result, incr, &basis, &iter,
-                                   1, execution_mode);
+      success = try_eval_const_alu(&result, incr, original, replacement,
+                                   2, execution_mode);
       assert(success);
 
-      iter = result;
+      replacement[0] = result;
    }
 
    return -1;
@@ -1141,8 +1144,8 @@
    case nir_op_ishr:
    case nir_op_ushr:
       return get_iteration_empirical(cond, alu, basis, initial,
-                                     invert_cond, execution_mode,
-                                     max_unroll_iterations);
+                                     limit_basis, limit, invert_cond,
+                                     execution_mode, max_unroll_iterations);
    default:
       unreachable("Invalid induction variable increment operation.");
    }

src/compiler/nir/tests/loop_analyze_tests.cpp

diff --git a/src/compiler/nir/tests/loop_analyze_tests.cpp b/src/compiler/nir/tests/loop_analyze_tests.cpp
index b9a2c5e..24415c9 100644
--- a/src/compiler/nir/tests/loop_analyze_tests.cpp
+++ b/src/compiler/nir/tests/loop_analyze_tests.cpp
@@ -302,6 +302,7 @@
 
 CMP_MIN(ige, imin)
 CMP_MIN_REV(ige, imin)
+CMP_MIN(uge, umin)
 CMP_MIN(ige, fmin)
 CMP_MIN(uge, imin)
 CMP_MIN(ilt, imin)
@@ -1614,3 +1615,13 @@
  *    }
  */
 INEXACT_COUNT_TEST(0x00000008, 0x00000004, 0xffffffff, ilt_imax, iadd, 5)
+
+/*    uint i = 0x00000001;
+ *    while (true) {
+ *       if (i >= umin(vertex_id, 0x00000100))
+ *          break;
+ *
+ *       i <<= 1;
+ *    }
+ */
+INEXACT_COUNT_TEST(0x00000001, 0x00000100, 0x00000001, uge_umin, ishl, 8)