Mesa (master): vc4: Try swapping the regfile A to B to pair instructions.
Eric Anholt
anholt at kemper.freedesktop.org
Sat Dec 6 00:32:40 UTC 2014
Module: Mesa
Branch: master
Commit: befdff81423a1b6a05969dfde59bfa9c521c4621
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=befdff81423a1b6a05969dfde59bfa9c521c4621
Author: Eric Anholt <eric at anholt.net>
Date: Fri Dec 5 13:23:17 2014 -0800
vc4: Try swapping the regfile A to B to pair instructions.
total instructions in shared programs: 56995 -> 56087 (-1.59%)
instructions in affected programs: 40503 -> 39595 (-2.24%)
---
src/gallium/drivers/vc4/vc4_qpu.c | 64 +++++++++++++++++++++++++++++++++++--
1 file changed, 62 insertions(+), 2 deletions(-)
diff --git a/src/gallium/drivers/vc4/vc4_qpu.c b/src/gallium/drivers/vc4/vc4_qpu.c
index 0e38890..6daa072 100644
--- a/src/gallium/drivers/vc4/vc4_qpu.c
+++ b/src/gallium/drivers/vc4/vc4_qpu.c
@@ -290,6 +290,55 @@ qpu_waddr_ignores_pm(uint32_t waddr)
return false;
}
+static void
+swap_ra_file_mux_helper(uint64_t *merge, uint64_t *a, uint32_t mux_shift)
+{
+ uint64_t mux_mask = (uint64_t)0x7 << mux_shift;
+ uint64_t mux_a_val = (uint64_t)QPU_MUX_A << mux_shift;
+ uint64_t mux_b_val = (uint64_t)QPU_MUX_B << mux_shift;
+
+ if ((*a & mux_mask) == mux_a_val) {
+ *a = (*a & ~mux_mask) | mux_b_val;
+ *merge = (*merge & ~mux_mask) | mux_b_val;
+ }
+}
+
+static bool
+try_swap_ra_file(uint64_t *merge, uint64_t *a, uint64_t *b)
+{
+ uint32_t raddr_a_a = QPU_GET_FIELD(*a, QPU_RADDR_A);
+ uint32_t raddr_a_b = QPU_GET_FIELD(*a, QPU_RADDR_B);
+ uint32_t raddr_b_a = QPU_GET_FIELD(*b, QPU_RADDR_A);
+ uint32_t raddr_b_b = QPU_GET_FIELD(*b, QPU_RADDR_B);
+
+ if (raddr_a_b != QPU_R_NOP)
+ return false;
+
+ switch (raddr_a_a) {
+ case QPU_R_UNIF:
+ case QPU_R_VARY:
+ break;
+ default:
+ return false;
+ }
+
+ if (raddr_b_b != QPU_R_NOP &&
+ raddr_b_b != raddr_a_a)
+ return false;
+
+ /* Move raddr A to B in instruction a. */
+ *a = (*a & ~QPU_RADDR_A_MASK) | QPU_SET_FIELD(QPU_R_NOP, QPU_RADDR_A);
+ *a = (*a & ~QPU_RADDR_B_MASK) | QPU_SET_FIELD(raddr_a_a, QPU_RADDR_B);
+ *merge = ((*merge & ~QPU_RADDR_A_MASK) | QPU_SET_FIELD(raddr_b_a, QPU_RADDR_A));
+ *merge = ((*merge & ~QPU_RADDR_B_MASK) | QPU_SET_FIELD(raddr_a_a, QPU_RADDR_B));
+ swap_ra_file_mux_helper(merge, a, QPU_ADD_A_SHIFT);
+ swap_ra_file_mux_helper(merge, a, QPU_ADD_B_SHIFT);
+ swap_ra_file_mux_helper(merge, a, QPU_MUL_A_SHIFT);
+ swap_ra_file_mux_helper(merge, a, QPU_MUL_B_SHIFT);
+
+ return true;
+}
+
uint64_t
qpu_merge_inst(uint64_t a, uint64_t b)
{
@@ -314,8 +363,19 @@ qpu_merge_inst(uint64_t a, uint64_t b)
ok = ok && merge_fields(&merge, a, b, QPU_SF | QPU_PM,
~0);
- ok = ok && merge_fields(&merge, a, b, QPU_RADDR_A_MASK,
- QPU_SET_FIELD(QPU_R_NOP, QPU_RADDR_A));
+ if (!merge_fields(&merge, a, b, QPU_RADDR_A_MASK,
+ QPU_SET_FIELD(QPU_R_NOP, QPU_RADDR_A))) {
+ /* Since we tend to use regfile A by default both for register
+ * allocation and for our special values (uniforms and
+ * varyings), try swapping uniforms and varyings to regfile B
+ * to resolve raddr A conflicts.
+ */
+ if (!try_swap_ra_file(&merge, &a, &b) &&
+ !try_swap_ra_file(&merge, &b, &a)) {
+ return 0;
+ }
+ }
+
ok = ok && merge_fields(&merge, a, b, QPU_RADDR_B_MASK,
QPU_SET_FIELD(QPU_R_NOP, QPU_RADDR_B));
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