[Mesa-dev] [PATCH] nir/opcodes: Fix constant-folding of bitfield_insert

[James Legg]

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104119
CC: <mesa-***@lists.freedesktop.org>
CC: Samuel Pitoiset <***@gmail.com>
---
src/compiler/nir/nir_opcodes.py | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/nir/nir_opcodes.py b/src/compiler/nir/nir_opcodes.py
index ac7333fe78..278562b2bd 100644
--- a/src/compiler/nir/nir_opcodes.py
+++ b/src/compiler/nir/nir_opcodes.py
@@ -724,12 +724,12 @@ opcode("bitfield_insert", 0, tuint32, [0, 0, 0, 0],
unsigned base = src0, insert = src1;
int offset = src2, bits = src3;
if (bits == 0) {
- dst = 0;
+ dst = base;
} else if (offset < 0 || bits < 0 || bits + offset > 32) {
dst = 0;
} else {
unsigned mask = ((1ull << bits) - 1) << offset;
- dst = (base & ~mask) | ((insert << bits) & mask);
+ dst = (base & ~mask) | ((insert << offset) & mask);
}
""")

[Matt Turner]

Post by James Legg
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104119
---
src/compiler/nir/nir_opcodes.py | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/compiler/nir/nir_opcodes.py b/src/compiler/nir/nir_opcodes.py
index ac7333fe78..278562b2bd 100644
--- a/src/compiler/nir/nir_opcodes.py
+++ b/src/compiler/nir/nir_opcodes.py
@@ -724,12 +724,12 @@ opcode("bitfield_insert", 0, tuint32, [0, 0, 0, 0],
unsigned base = src0, insert = src1;
int offset = src2, bits = src3;
if (bits == 0) {
- dst = 0;
+ dst = base;
} else if (offset < 0 || bits < 0 || bits + offset > 32) {
dst = 0;
} else {
unsigned mask = ((1ull << bits) - 1) << offset;
- dst = (base & ~mask) | ((insert << bits) & mask);
+ dst = (base & ~mask) | ((insert << offset) & mask);
}
""")

Reviewed-by: Matt Turner <***@gmail.com>

[Alex Smith]

Pushed.

Post by James Legg

Post by James Legg
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104119
---
src/compiler/nir/nir_opcodes.py | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/compiler/nir/nir_opcodes.py b/src/compiler/nir/nir_

opcodes.py

Post by James Legg
index ac7333fe78..278562b2bd 100644
--- a/src/compiler/nir/nir_opcodes.py
+++ b/src/compiler/nir/nir_opcodes.py
@@ -724,12 +724,12 @@ opcode("bitfield_insert", 0, tuint32, [0, 0, 0, 0],
unsigned base = src0, insert = src1;
int offset = src2, bits = src3;
if (bits == 0) {
- dst = 0;
+ dst = base;
} else if (offset < 0 || bits < 0 || bits + offset > 32) {
dst = 0;
} else {
unsigned mask = ((1ull << bits) - 1) << offset;
- dst = (base & ~mask) | ((insert << bits) & mask);
+ dst = (base & ~mask) | ((insert << offset) & mask);
}
""")

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