Merge pull request #3550 from alexcrichton/close-simd-fuzz

x64: Add test for a fixed issue

tests/misc_testsuite/simd/almost-extmul.wast

@@ -0,0 +1,16 @@
+;; regression test from #3337, there's a multiplication that sort of
+;; looks like an extmul and codegen shouldn't pattern match too much
+(module
+  (type (;0;) (func))
+  (func (;0;) (type 0)
+    v128.const i32x4 0x00000000 0x00000000 0x00000000 0x00000000
+    i64x2.extend_low_i32x4_u
+    v128.const i32x4 0x00000000 0x00000000 0x00000000 0x00000000
+    i64x2.mul
+    i32x4.all_true
+    i64.load offset=1 align=1
+    drop
+    unreachable)
+  (func (;1;) (type 0)
+    nop)
+  (memory (;0;) 1 1))