From f40c9d02254cd26d2ff92e3f42825fcd7badad92 Mon Sep 17 00:00:00 2001 From: Gert Wollny Date: Tue, 5 Jun 2018 22:26:37 +0200 Subject: [PATCH] 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 Acked-by: Dave Airlie --- .../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 6921a643b74..8f572ecd2d2 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 acebfb82935..fcd5fda14eb 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 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. -- 2.11.0