[Mesa-dev] [PATCH] radeonsi: fix a regression in si_eliminate_const_output

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

A constant value of float type is not necessarily a ConstantFP: it could also
be a constant expression that for some reason hasn't been folded.

This fixes a regression in GL45-CTS.arrays_of_arrays_gl.InteractionFunctionCalls2
that was introduced by commit 3ec9975555d1cc5365413ad9062f412904f944a3.
---
 src/gallium/drivers/radeonsi/si_shader.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 3a84253..5eebf29 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -6528,37 +6528,36 @@ static bool si_eliminate_const_output(struct si_shader_context *ctx,
 				      LLVMValueRef inst, unsigned offset)
 {
 	struct si_shader *shader = ctx->shader;
 	unsigned num_outputs = shader->selector->info.num_outputs;
 	unsigned i, default_val; /* SPI_PS_INPUT_CNTL_i.DEFAULT_VAL */
 	bool is_zero[4] = {}, is_one[4] = {};
 
 	for (i = 0; i < 4; i++) {
 		LLVMBool loses_info;
 		LLVMValueRef p = LLVMGetOperand(inst, 5 + i);
-		if (!LLVMIsConstant(p))
-			return false;
 
 		/* It's a constant expression. Undef outputs are eliminated too. */
 		if (LLVMIsUndef(p)) {
 			is_zero[i] = true;
 			is_one[i] = true;
-		} else {
+		} else if (LLVMIsAConstantFP(p)) {
 			double a = LLVMConstRealGetDouble(p, &loses_info);
 
 			if (a == 0)
 				is_zero[i] = true;
 			else if (a == 1)
 				is_one[i] = true;
 			else
 				return false; /* other constant */
-		}
+		} else
+			return false;
 	}
 
 	/* Only certain combinations of 0 and 1 can be eliminated. */
 	if (is_zero[0] && is_zero[1] && is_zero[2])
 		default_val = is_zero[3] ? 0 : 1;
 	else if (is_one[0] && is_one[1] && is_one[2])
 		default_val = is_zero[3] ? 2 : 3;
 	else
 		return false;
 
-- 
2.7.4