From: Aleksey Demakov <ademakov@gmail.com>
Date: Sun, 28 Jan 2007 20:14:57 +0000 (+0000)
Subject: fix bug with input register thrashing introduced 2006-12-30
X-Git-Tag: before.move.to.git~157
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=cab0deaa5a93ef9f1013f266873b9ef9efc0d322;p=francis%2Flibjit.git

fix bug with input register thrashing introduced 2006-12-30
---

diff --git a/ChangeLog b/ChangeLog
index 9fe901b..fef5ee0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,8 @@
 2007-01-28  Aleksey Demakov  <ademakov@gmail.com>
 
-	* jit/jit-reg-alloc.c (_jit_regs_gen): fix recently introduced bug
-	with loading registers for ternary ops.
+	* jit/jit-reg-alloc.c (_jit_regs_gen, set_regdesc_flags): fix bugs
+	introduced 2006-12-30 with loading registers for ternary ops and
+	handling input register thrash.
 
 2007-01-26  Aleksey Demakov  <ademakov@gmail.com>
 
diff --git a/jit/jit-reg-alloc.c b/jit/jit-reg-alloc.c
index 7910772..2e0960c 100644
--- a/jit/jit-reg-alloc.c
+++ b/jit/jit-reg-alloc.c
@@ -689,7 +689,6 @@ set_regdesc_flags(jit_gencode_t gen, _jit_regs_t *regs, int index)
 			{
 				reg = -1;
 				other_reg = -1;
-				desc->store = 1;
 			}
 		}
 
@@ -726,9 +725,8 @@ set_regdesc_flags(jit_gencode_t gen, _jit_regs_t *regs, int index)
 			clobber_input = ((clobber & CLOBBER_INPUT_VALUE) != 0);
 		}
 
-		/* See if the input value needs to be saved before the
-		   instruction and if it stays or not in the register
-		   after the instruction. */
+		/* See if the input value needs to be stored before the
+		   instruction and if it stays in the register after it. */
 		if(desc->value->is_constant)
 		{
 			desc->kill = 1;
@@ -744,6 +742,12 @@ set_regdesc_flags(jit_gencode_t gen, _jit_regs_t *regs, int index)
 			desc->kill = 1;
 		}
 
+		/* Store the value if it is going to be thrashed by another one. */
+		if(desc->thrash)
+		{
+			desc->store = 1;
+		}
+
 #ifdef JIT_REG_STACK
 		/* Count stack registers. */
 		if(IS_STACK_REG(desc->reg))