summary refs log tree commit diff
path: root/test/rega1.ssa
diff options
context:
space:
mode:
authorQuentin Carbonneaux <quentin@c9x.me>2019-02-06 08:34:51 +0100
committerQuentin Carbonneaux <quentin@c9x.me>2019-02-06 09:02:25 +0100
commitce0ab53ed73fb24f9537cab762467efad56f2664 (patch)
treef8fb8d9da412938e1d66d7fc2b7a7f98f7a64f19 /test/rega1.ssa
parent834b5cb08bbf0f4fbc1992a72327dfc2c0a31796 (diff)
downloadroux-ce0ab53ed73fb24f9537cab762467efad56f2664.tar.gz
2 bug fixes in rega
The worst one was that "part 3" of rega()
could break the critical invariant that
two interferring temporaries get assigned
different registers.  This is fixed by
being careful when changing the register
of a temporary based on predecessor
blocks.

Thanks to Michael Forney for reporting
these bugs and helping with the analysis.
Diffstat (limited to 'test/rega1.ssa')
-rw-r--r--test/rega1.ssa24
1 files changed, 24 insertions, 0 deletions
diff --git a/test/rega1.ssa b/test/rega1.ssa
new file mode 100644
index 0000000..9e87c89
--- /dev/null
+++ b/test/rega1.ssa
@@ -0,0 +1,24 @@
+# tests that %b and %a0 do not end up in
+# the same register at the start of @loop
+
+export function l $f(l %a) {
+@start
+@loop
+	%b =l phi @start 42, @loop0 %a1, @loop1 %a1
+	%a0 =l phi @start %a, @loop0 %a1, @loop1 %a1
+	%a1 =l sub %a0, 1
+	jnz %b, @loop0, @loop1
+@loop0
+	jnz %a1, @loop, @end
+@loop1
+	jnz %a1, @loop, @end
+@end
+	ret %b
+}
+
+# >>> driver
+# extern long long f(long long);
+# int main() {
+# 	return !(f(1) == 42 && f(2) == 1 && f(42) == 1);
+# }
+# <<<