Fixes: 807e2539e512ca6c96f059da855473eb7be99ba1
mesa/st/glsl_to_tgsi: Add tracking of ifelse writes in register merging
Bugzilla:
https://urldefense.proofpoint.com/v2/url?u=https-3A__bugs.freedesktop.org_show-5Fbug.cgi-3Fid-3D104803&d=DwIBAg&c=uilaK90D4TOVoH58JNXRgQ&r=Ie7_encNUsqxbSRbqbNgofw0ITcfE8JKfaUjIQhncGA&m=HYtcsBqPlkbxRGKakM7-fRJbICIqO4cx61Ah07d_cUw&s=bp-ajSeskM47lfjWPMZYje1thrrlRao8t7EUbblmU3I&e=
Signed-off-by: Gert Wollny <gw.foss...@gmail.com>
---
.../state_tracker/st_glsl_to_tgsi_temprename.cpp | 24 +++++++++++++++++++++-
.../tests/test_glsl_to_tgsi_lifetime.cpp | 24 ++++++++++++++++++++++
2 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
b/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
index 3a00b33749..6921a643b7 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
@@ -197,6 +197,7 @@ private:
static const int write_is_conditional = -1;
static const int conditionality_unresolved = 0;
static const int conditionality_untouched;
+ static const int write_is_unconditional;
/* A bit field tracking the nexting levels of if-else clauses where the
* temporary has (so far) been written to in the if branch, but not in the
@@ -220,6 +221,9 @@ private:
const int
temp_comp_access::conditionality_untouched = numeric_limits<int>::max();
+const int
+temp_comp_access::write_is_unconditional = numeric_limits<int>::max() - 1;
+
/* Class to track the access to all components of a temporary register. */
class temp_access {
public:
@@ -566,6 +570,13 @@ void temp_comp_access::record_read(int line, prog_scope
*scope)
first_read_scope = scope;
}
+ /* If the conditionality of the first write is already resolved then
+ * no further checks are required.
+ */
+ if (conditionality_in_loop_id == write_is_unconditional ||
+ conditionality_in_loop_id == write_is_conditional)
+ return;
+
/* Check whether we are in a condition within a loop */
const prog_scope *ifelse_scope = scope->in_ifelse_scope();
const prog_scope *enclosing_loop;
@@ -612,9 +623,20 @@ void temp_comp_access::record_write(int line, prog_scope
*scope)
if (first_write < 0) {
first_write = line;
first_write_scope = scope;
+
+ /* If the first write we encounter is not in a conditional branch, or
+ * the conditional write is not within a loop, then this is to be
+ * considered an unconditional dominant write.
+ */
+ const prog_scope *conditional = scope->enclosing_conditional();
+ if (!conditional || !conditional->innermost_loop()) {
+ conditionality_in_loop_id = write_is_unconditional;
+ }
}
- if (conditionality_in_loop_id == write_is_conditional)
+ /* The conditionality of the first write is already resolved. */
+ if (conditionality_in_loop_id == write_is_unconditional ||
+ conditionality_in_loop_id == write_is_conditional)
return;
/* If the nesting depth is larger than the supported level,
diff --git a/src/mesa/state_tracker/tests/test_glsl_to_tgsi_lifetime.cpp
b/src/mesa/state_tracker/tests/test_glsl_to_tgsi_lifetime.cpp
index a3b0f0e02f..acebfb8293 100644
--- a/src/mesa/state_tracker/tests/test_glsl_to_tgsi_lifetime.cpp
+++ b/src/mesa/state_tracker/tests/test_glsl_to_tgsi_lifetime.cpp
@@ -794,6 +794,30 @@ TEST_F(LifetimeEvaluatorExactTest,
WriteInIfElseBranchSecondIfInLoop)
run (code, temp_lt_expect({{-1,-1}, {2,9}}));
}
+/** Regression test for bug #104803,
+ * Read and write in if/else path outside loop and later read in conditional
+ * within a loop. The first write is to be considered the dominant write.
+ */
+TEST_F(LifetimeEvaluatorExactTest,
IfElseWriteInBothOutsideLoopReadInElseInLoop)
+{
+ const vector<FakeCodeline> code = {
+ { TGSI_OPCODE_IF, {}, {in0}, {} },
+ { TGSI_OPCODE_MOV, {1}, {in0}, {} },
+ { TGSI_OPCODE_ELSE, {}, {}, {} },
+ { TGSI_OPCODE_MOV, {1}, {in1}, {} },
+ { TGSI_OPCODE_ENDIF, {}, {}, {} },
+ { TGSI_OPCODE_BGNLOOP },
+ { TGSI_OPCODE_IF, {}, {in0}, {} },
+ { TGSI_OPCODE_MOV, {2}, {in1}, {} },
+ { TGSI_OPCODE_ELSE, {}, {}, {} },
+ { TGSI_OPCODE_MOV, {2}, {1}, {} },
+ { TGSI_OPCODE_ENDIF, {}, {}, {} },
+ { TGSI_OPCODE_ENDLOOP },
+ { TGSI_OPCODE_MOV, {out0}, {2}, {}},
+ { TGSI_OPCODE_END}
+ };
+ run (code, temp_lt_expect({{-1,-1}, {1,11}, {7, 12}}));
+}
/* A continue in the loop is not relevant */
TEST_F(LifetimeEvaluatorExactTest, LoopWithWriteAfterContinue)
