wingo pushed a commit to branch lightning
in repository guile.
commit 45c4df506c31a38be1a18d76dac0a8d12fd9d423
Author: pcpa <[email protected]>
Date: Mon Sep 1 16:27:19 2014 -0300
Only mark callee save regs as live on jumps that cannot be tracked.
* lib/lightning.c: Do not mark all registers in unknown state
as live on jit_jmpr, or jit_jmpi to an absolute address. Instead,
treat it as a function call, and only consider JIT_Vn registers
as possibly live.
---
ChangeLog | 7 +++++++
lib/lightning.c | 27 +++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 1c88395..97c8f47 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-09-01 Paulo Andrade <[email protected]>
+
+ * lib/lightning.c: Do not mark all registers in unknown state
+ as live on jit_jmpr, or jit_jmpi to an absolute address. Instead,
+ treat it as a function call, and only consider JIT_Vn registers
+ as possibly live.
+
2014-08-29 Paulo Andrade <[email protected]>
* doc/body.texi: Add a proper info menu entry for
diff --git a/lib/lightning.c b/lib/lightning.c
index d816a45..a8a9463 100644
--- a/lib/lightning.c
+++ b/lib/lightning.c
@@ -2006,6 +2006,7 @@ _jit_update(jit_state_t *_jit, jit_node_t *node,
jit_regset_t *live, jit_regset_t *mask)
{
jit_int32_t spec;
+ jit_int32_t regno;
jit_regset_t ztmp;
jit_regset_t zmask;
unsigned long value;
@@ -2165,6 +2166,32 @@ _jit_update(jit_state_t *_jit, jit_node_t *node,
}
continue;
}
+ /* Should not really mark as live all registers in unknown
+ * state if using jit_jmpr(), or jit_jmpi(absolute_address)
+ * because that would leave the register allocator with
+ * no options for "nospill" temporaries (other temporaries
+ * also benefit from not needing to spill/reload), so, the
+ * user must ensure to either spill/reload, or only leave
+ * live registers on JIT_Vn if using a jump that cannot
+ * be tracked around the generated jit code */
+ for (spec = JIT_R_NUM - 1; spec >= 0; spec--) {
+ regno = jit_r(spec);
+ if (jit_regset_tstbit(mask, regno))
+ jit_regset_clrbit(mask, regno);
+ }
+ for (spec = JIT_F_NUM - 1; spec >= 0; spec--) {
+ regno = jit_f(spec);
+ if (jit_regset_tstbit(mask, regno))
+ jit_regset_clrbit(mask, regno);
+ }
+ /* In some backends JIT_Rn and JIT_Fn are callee save */
+ for (regno = 0; regno < _jitc->reglen; regno++) {
+ spec = jit_class(_rvs[regno].spec);
+ if (jit_regset_tstbit(mask, regno) &&
+ (spec & (jit_class_gpr|jit_class_fpr)) &&
+ !(spec & jit_class_sav))
+ jit_regset_clrbit(mask, regno);
+ }
/* assume value is live due to jump to unknown location */
jit_regset_ior(live, live, mask);
jit_regset_set_ui(mask, 0);
