Module: Mesa
Branch: master
Commit: f40c9d02254cd26d2ff92e3f42825fcd7badad92
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=f40c9d02254cd26d2ff92e3f42825fcd7badad92
Author: Gert Wollny <gw.foss...@gmail.com>
Date: Tue Jun 5 22:26:37 2018 +0200
mesa/st/glsl_to_tgsi: Properly resolve life times simple if/else + use
constructs
in constructs like below, currently the live range estimation extends the live
range
of t unecessarily to the whole loop because it was not detected that t is
unconditional written and later read only in the "if (a)" scope.
while (foo) {
...
if (a) {
...
if (b)
t = ...
else
t = ...
x = t;
...
}
...
}
This patch adds a unit test for this case and corrects the minimal live range
estimation
accordingly.
v4: update comments
Signed-off-by: Gert Wollny <gw.foss...@gmail.com>
Acked-by: Dave Airlie <airl...@redhat.com>
---
.../state_tracker/st_glsl_to_tgsi_temprename.cpp | 14 ++++++++++++
.../tests/test_glsl_to_tgsi_lifetime.cpp | 25 ++++++++++++++++++++++
2 files changed, 39 insertions(+)
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 6921a643b7..8f572ecd2d 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi_temprename.cpp
@@ -741,6 +741,20 @@ void temp_comp_access::record_else_write(const prog_scope&
scope)
} else {
current_unpaired_if_write_scope = nullptr;
}
+ /* Promote the first write scope to the enclosing scope because
+ * the current IF/ELSE pair is now irrelevant for the analysis.
+ * This is also required to evaluate the minimum life time for t in
+ * {
+ * var t;
+ * if (a)
+ * t = ...
+ * else
+ * t = ...
+ * x = t;
+ * ...
+ * }
+ */
+ first_write_scope = scope.parent();
/* If some parent is IF/ELSE and in a loop then propagate the
* write to that scope. Otherwise the write is unconditional
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 acebfb8293..fcd5fda14e 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 +794,31 @@ TEST_F(LifetimeEvaluatorExactTest,
WriteInIfElseBranchSecondIfInLoop)
run (code, temp_lt_expect({{-1,-1}, {2,9}}));
}
+/* Within an IF clause within a loop test that if a write occured in both
+ * branches of a nested IF/ELSE clause, followed by the last read within the
+ * enclosing IF or ELSE clause, the combined read is registered as
unconditional,
+ * i.e.that it doesn't extend its live range beyond that enclosing IF or ELSE
+ * clause.
+ */
+TEST_F(LifetimeEvaluatorExactTest, DeeplyNestedinLoop)
+{
+ const vector<FakeCodeline> code = {
+ { TGSI_OPCODE_BGNLOOP },
+ { TGSI_OPCODE_UIF, {}, {in0}, {}},
+ { TGSI_OPCODE_FSEQ, {1}, {in1,in2}, {}},
+ { TGSI_OPCODE_UIF, {}, {1}, {}},
+ { TGSI_OPCODE_MOV, {2}, {in1}, {}},
+ { TGSI_OPCODE_ELSE },
+ { TGSI_OPCODE_MOV, {2}, {in2}, {}},
+ { TGSI_OPCODE_ENDIF },
+ { TGSI_OPCODE_MOV, {3}, {2}, {}},
+ { TGSI_OPCODE_ENDIF },
+ { TGSI_OPCODE_ADD, {out0}, {3, in1}, {}},
+ { TGSI_OPCODE_ENDLOOP }
+ };
+ run (code, temp_lt_expect({{-1,-1}, {2,3}, {4, 8}, {0,11}}));
+}
+
/** 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.
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