From 3d6ee435cf6ebf94dbd3ba9ea0eca4070e5eff65 Mon Sep 17 00:00:00 2001
From: George Koehler <xkernigh@netscape.net>
Date: Sun, 29 Oct 2017 14:53:33 -0400
Subject: [PATCH] Fix pattern that was rewriting func(! var, var) as func(1).

Bug reported by Rune, see
 - https://sourceforge.net/p/tack/mailman/message/35809953/
 - https://github.com/davidgiven/ack/issues/62

In EM code, beq and bne pop 2 values and compare them, but teq and tne
pop only 1 value and compare it with zero.  We need cms to compare 2
values; other patterns may convert cmi or cmu to cms.
---
 tests/plat/bugs/bug-62-notvar_var_e.c | 49 +++++++++++++++++++++++++++
 tests/plat/build.lua                  |  3 +-
 util/opt/patterns                     | 12 +++----
 3 files changed, 57 insertions(+), 7 deletions(-)
 create mode 100644 tests/plat/bugs/bug-62-notvar_var_e.c

diff --git a/tests/plat/bugs/bug-62-notvar_var_e.c b/tests/plat/bugs/bug-62-notvar_var_e.c
new file mode 100644
index 000000000..d3813bb91
--- /dev/null
+++ b/tests/plat/bugs/bug-62-notvar_var_e.c
@@ -0,0 +1,49 @@
+#include "test.h"
+
+/*
+ * Function a() comes from this mail by Rune to tack-devel:
+ * https://sourceforge.net/p/tack/mailman/message/35809953/
+ *
+ * The peephole optimiser (util/opt) had a bug that rewrote
+ * xx(! i, i) as xx(1).  It was confused with xx(i == i).
+ */
+
+void xx(int xfal, int x1234) {
+  ASSERT(xfal == 0);
+  ASSERT(x1234 == 1234);
+}
+
+void a(void) {
+  int i = 1234;
+  xx(! i, i);
+}
+
+void xxxx(int x2005, int xfal, int xn567, int x2017) {
+  ASSERT(x2005 == 2005);
+  ASSERT(xfal == 0);
+  ASSERT(xn567 == -567);
+  ASSERT(x2017 == 2017);
+}
+
+/* Like a(), but with surrounding arguments. */
+void b(void) {
+  int i = -567;
+  xxxx(2005, ! i, i, 2017);
+}
+
+/*
+ * In c(), the fixed peephole optimiser may
+ * rewrite i == i as 1 and i != i as 0.
+ */
+void c(int i, int tru, int fal) {
+  ASSERT((i == i) == tru);
+  ASSERT((i != i) == fal);
+}
+
+/* Bypasses the CRT. */
+void _m_a_i_n(void) {
+  a();
+  b();
+  c(62, 1, 0);
+  finished();
+}
diff --git a/tests/plat/build.lua b/tests/plat/build.lua
index b689ea5f6..12611711a 100644
--- a/tests/plat/build.lua
+++ b/tests/plat/build.lua
@@ -13,7 +13,8 @@ definerule("plat_testsuite",
 			"tests/plat/*.e",
 			"tests/plat/*.p",
 			"tests/plat/b/*.b",
-			"tests/plat/bugs/*.mod"
+			"tests/plat/bugs/bug-22-inn_mod.mod",
+			"tests/plat/bugs/bug-62-notvar_var_e.c"
 		)
 
 		acklibrary {
diff --git a/util/opt/patterns b/util/opt/patterns
index 8d949dfd8..34bcc760a 100644
--- a/util/opt/patterns
+++ b/util/opt/patterns
@@ -641,13 +641,13 @@ lol lol bne $1==$2 :
 loe loe bne $1==$2 :
 lil lil bne $1==$2 :
 
-lol lol teq $1==$2 : loc 1
-loe loe teq $1==$2 : loc 1
-lil lil teq $1==$2 : loc 1
+lol lol cms teq $1==$2 && $3==w : loc 1
+loe loe cms teq $1==$2 && $3==w : loc 1
+lil lil cms teq $1==$2 && $3==w : loc 1
 
-lol lol tne $1==$2 : loc 0
-loe loe tne $1==$2 : loc 0
-lil lil tne $1==$2 : loc 0
+lol lol cms tne $1==$2 && $3==w : loc 0
+loe loe cms tne $1==$2 && $3==w : loc 0
+lil lil cms tne $1==$2 && $3==w : loc 0
 
 lol loc CBO stl $3==w && $1==$4 : loc $2 lol $1 CBO w stl $4
 lol loe CBO stl $3==w && $1==$4 : loe $2 lol $1 CBO w stl $4