From d604855b27f4656423465cdf7774631c1134c8aa Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Tue, 14 Mar 2017 13:31:01 -0700
Subject: [PATCH] Fix logic bug in requires_typevar_operand.

The Python code computing this property had a bug. The property has only
been used for optimizing the ctrl_typevar() method so far.
---
 lib/cretonne/meta/gen_instr.py      |  2 +-
 lib/cretonne/src/ir/instructions.rs | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/lib/cretonne/meta/gen_instr.py b/lib/cretonne/meta/gen_instr.py
index 02677bfdbd..f3c36a716f 100644
--- a/lib/cretonne/meta/gen_instr.py
+++ b/lib/cretonne/meta/gen_instr.py
@@ -445,7 +445,7 @@ def gen_type_constraints(fmt, instrs):
             use_typevar_operand = i.is_polymorphic and i.use_typevar_operand
             # Can the controlling type variable be inferred from the result?
             use_result = (fixed_results > 0 and
-                          i.outs[i.value_results[0]].typevar != ctrl_typevar)
+                          i.outs[i.value_results[0]].typevar == ctrl_typevar)
             # Are we required to use the designated operand instead of the
             # result?
             requires_typevar_operand = use_typevar_operand and not use_result
diff --git a/lib/cretonne/src/ir/instructions.rs b/lib/cretonne/src/ir/instructions.rs
index 7e970f73b8..c51afcc118 100644
--- a/lib/cretonne/src/ir/instructions.rs
+++ b/lib/cretonne/src/ir/instructions.rs
@@ -627,9 +627,16 @@ mod tests {
     fn constraints() {
         let a = Opcode::Iadd.constraints();
         assert!(a.use_typevar_operand());
+        assert!(!a.requires_typevar_operand());
         assert_eq!(a.fixed_results(), 1);
         assert_eq!(a.fixed_value_arguments(), 2);
 
+        let b = Opcode::Bitcast.constraints();
+        assert!(!b.use_typevar_operand());
+        assert!(!b.requires_typevar_operand());
+        assert_eq!(b.fixed_results(), 1);
+        assert_eq!(b.fixed_value_arguments(), 1);
+
         let c = Opcode::Call.constraints();
         assert_eq!(c.fixed_results(), 0);
         assert_eq!(c.fixed_value_arguments(), 0);
@@ -637,6 +644,12 @@ mod tests {
         let i = Opcode::CallIndirect.constraints();
         assert_eq!(i.fixed_results(), 0);
         assert_eq!(i.fixed_value_arguments(), 1);
+
+        let cmp = Opcode::Icmp.constraints();
+        assert!(cmp.use_typevar_operand());
+        assert!(cmp.requires_typevar_operand());
+        assert_eq!(cmp.fixed_results(), 1);
+        assert_eq!(cmp.fixed_value_arguments(), 2);
     }
 
     #[test]