Mesa (master): panfrost/midgard: Add missing lowering passes for type/size conversion ops

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Module: Mesa
Branch: master
Commit: 5b810c7de303e32900fed18b1303648eb74a6415
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=5b810c7de303e32900fed18b1303648eb74a6415

Author: Boris Brezillon <boris.brezillon at collabora.com>
Date:   Mon Jan 20 22:02:40 2020 +0100

panfrost/midgard: Add missing lowering passes for type/size conversion ops

Replace the manual type/size conversion lowering description by one
that's automatically generated and covers all type/size conversions.

Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3478>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3478>

---

 src/panfrost/midgard/midgard_nir_algebraic.py | 47 +++++++++++++++++++--------
 1 file changed, 34 insertions(+), 13 deletions(-)

diff --git a/src/panfrost/midgard/midgard_nir_algebraic.py b/src/panfrost/midgard/midgard_nir_algebraic.py
index 951b4b23241..2ba9f226d22 100644
--- a/src/panfrost/midgard/midgard_nir_algebraic.py
+++ b/src/panfrost/midgard/midgard_nir_algebraic.py
@@ -48,19 +48,40 @@ algebraic_late = [
 # Midgard is able to type convert down by only one "step" per instruction; if
 # NIR wants more than one step, we need to break up into multiple instructions
 
-converts = [
-    (('i2i8', 'a at 32'), ('i2i8', ('i2i16', a))),
-    (('u2u8', 'a at 32'), ('u2u8', ('u2u16', a))),
-
-    (('i2i32', 'a at 8'), ('i2i32', ('i2i16', a))),
-    (('u2u32', 'a at 8'), ('u2u32', ('u2u16', a))),
-
-    (('f2i32', 'a at 16'), ('f2i32', ('f2f32', a))),
-    (('f2u32', 'a at 16'), ('f2u32', ('f2f32', a))),
-
-    # Totally redundant
-    (('~f2f16', ('f2f32', 'a at 16')), a),
-]
+converts = []
+
+for op in ('u2u', 'i2i', 'f2f', 'i2f', 'u2f', 'f2i', 'f2u'):
+    srcsz_max = 64
+    dstsz_max = 64
+    # 8 bit float doesn't exist
+    srcsz_min = 8 if op[0] != 'f' else 16
+    dstsz_min = 8 if op[2] != 'f' else 16
+    dstsz = dstsz_min
+    # Iterate over all possible destination and source sizes
+    while dstsz <= dstsz_max:
+        srcsz = srcsz_min
+        while srcsz <= srcsz_max:
+            # Size converter lowering is only needed if src and dst sizes are
+            # spaced by a factor > 2.
+            # Type converter lowering is needed as soon as src_size != dst_size
+            if srcsz != dstsz and ((srcsz * 2 != dstsz and srcsz != dstsz * 2) or op[0] != op[2]):
+                cursz = srcsz
+                rule = a
+                # When converting down we first do the type conversion followed
+                # by one or more size conversions. When converting up, we do
+                # the type conversion at the end. This way we don't have to
+                # deal with the fact that f2f8 doesn't exists.
+                sizeconvop = op[0] + '2' + op[0] if srcsz < dstsz else op[2] + '2' + op[2]
+                if srcsz > dstsz and op[0] != op[2]:
+                    rule = (op + str(int(cursz)), rule)
+                while cursz != dstsz:
+                    cursz = cursz / 2 if dstsz < srcsz else cursz * 2
+                    rule = (sizeconvop + str(int(cursz)), rule)
+                if srcsz < dstsz and op[0] != op[2]:
+                    rule = (op + str(int(cursz)), rule)
+                converts += [((op + str(int(dstsz)), 'a@' + str(int(srcsz))), rule)]
+            srcsz *= 2
+        dstsz *= 2
 
 # Midgard scales fsin/fcos arguments by pi.
 # Pass must be run only once, after the main loop