diff options
| author | Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com> | 2019-08-28 10:56:52 +0200 |
|---|---|---|
| committer | Dylan Baker <dylan@pnwbakers.com> | 2019-09-04 11:57:07 -0700 |
| commit | efa4aee99d918a0efaed798e7911f32f903cad23 (patch) | |
| tree | ef889d9a61f895bd61a21577b7e9669c1a3c5e7e | |
| parent | ec74c76a1a52c8536b85cbfcad851789b94979c2 (diff) | |
glsl: replace 'x + (-x)' with constant 0
This fixes a hang in shadertoy for radeonsi where a buffer was initialized with:
value -= value
with value being undefined.
In this case LLVM replace the operation with an assignment to NaN.
Cc: 19.1 19.2 <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111241
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
(cherry picked from commit 47cc660d9c19572e5ef2dce7c8ae1766a2ac9885)
| -rw-r--r-- | src/compiler/glsl/opt_algebraic.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/compiler/glsl/opt_algebraic.cpp b/src/compiler/glsl/opt_algebraic.cpp index ff4be269578..3147d25aea8 100644 --- a/src/compiler/glsl/opt_algebraic.cpp +++ b/src/compiler/glsl/opt_algebraic.cpp @@ -507,6 +507,18 @@ ir_algebraic_visitor::handle_expression(ir_expression *ir) if (is_vec_zero(op_const[1])) return ir->operands[0]; + /* Replace (x + (-x)) with constant 0 */ + for (int i = 0; i < 2; i++) { + if (op_expr[i]) { + if (op_expr[i]->operation == ir_unop_neg) { + ir_rvalue *other = ir->operands[(i + 1) % 2]; + if (other && op_expr[i]->operands[0]->equals(other)) { + return ir_constant::zero(ir, ir->type); + } + } + } + } + /* Reassociate addition of constants so that we can do constant * folding. */ |