asm mode: allow constants to be deleted

they have to be somewhere in the executable if they are not internal
but they can be validated all at once out-of-band

ir/memory.cpp

@@ -2370,6 +2370,15 @@ Memory::refined(const Memory &other, bool fncall,
     Pointer q(other, p());
     if (p.isByval().isTrue() && q.isByval().isTrue())
       continue;
+
+    // In assembly mode we verify each function individually and
+    // global constants are not validated (assumed to be correct).
+    // Hence we may not have all initializers if tgt doesn't reference them.
+    if (other.isAsmMode() &&
+        is_constglb(bid) &&
+        isInitialMemBlock(other.non_local_block_val[bid].val))
+      continue;
+
     ret &= (ptr_bid == bid_expr).implies(blockRefined(p, q, bid, undef_vars));
   }
 

tests/alive-tv/asm/const-delete.src.ll

@@ -0,0 +1,8 @@
+; TEST-ARGS: -tgt-is-asm
+
+@bar = constant i32 6
+
+define <4 x i32> @f(ptr %RP) {
+   %LGV = load i32, ptr @bar, align 4
+   ret <4 x i32> zeroinitializer
+}

tests/alive-tv/asm/const-delete.tgt.ll

@@ -0,0 +1,5 @@
+;@bar = constant i32 6
+
+define <4 x i32> @f(ptr %RP) {
+   ret <4 x i32> zeroinitializer
+}