ASM Backend: Fix comparisons involving OFFSETs and IMMediates

- Fix bad code generated for comparisons such as IF @globalvar = 0 THEN
- add tests to /tests/expressions/address-comparison.bas

Author: jayrm

changelog.txt

@@ -62,6 +62,7 @@ Version 1.06.0
 - #878: Fix fbc-64bit hangs on 'Case True' + 'Case False' inside 'Select Case As const'
 - Fix SELECT CASE AS CONST to allow both signed & unsigned case range values
 - #822, #814, #842: Compiler crash when initializing static/shared reference (DIM SHARED/STATIC BYREF) with non-constant initializer (e.g. another reference, or dynamic array element)
+- ASM backend: Fix bad code generated for comparisons such as IF @globalvar = 0 THEN
 
 
 Version 1.05.0

src/compiler/ir-tac.bas

@@ -2019,6 +2019,8 @@ private sub hFlushCOMP _
 		doload = TRUE
 	elseif( v1_typ = IR_VREGTYPE_IMM) then          '' /
 		doload = TRUE
+	elseif( v1_typ = IR_VREGTYPE_OFS and v2_typ = IR_VREGTYPE_IMM ) then
+		doload = TRUE
 	elseif( v2_typ <> IR_VREGTYPE_REG ) then        '' /
 		if( v2_typ <> IR_VREGTYPE_IMM ) then
 			doload = TRUE

tests/expressions/address-comparison.bas

@@ -1,8 +1,113 @@
 #include "fbcunit.bi"
 
+type T
+	__ as integer
+end type
+
+dim shared integer_shared as integer
+static shared integer_static_shared as integer
+
+dim shared T_shared as T
+static shared T_static_shared as T
+
 SUITE( fbc_tests.expressions.address_comparison )
 
-	TEST( testproc )
+	'' test that address of globals generates valid code
+	'' fbc 1.05.0 and earlier would generate invalid ASM for
+	'' CMP instruction: CMP IMM, OFFSET
+
+	TEST( compare_shared_literal )
+		
+		dim integer_local as integer
+		static integer_static as integer
+
+		dim T_local as T
+		static T_static as T
+
+		CU_ASSERT( @integer_shared <> 0 )
+
+		if( @integer_shared = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @integer_shared <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @integer_static_shared <> 0 )
+
+		if( @integer_static_shared = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @integer_static_shared <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @integer_local <> 0 )
+
+		if( @integer_local = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @integer_local <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @integer_static <> 0 )
+
+		if( @integer_static = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @integer_static <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @T_shared <> 0 )
+
+		if( @T_shared = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @T_shared <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @T_static_shared <> 0 )
+
+		if( @T_static_shared = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @T_static_shared <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @T_local <> 0 )
+
+		if( @T_local = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @T_local <> 0 ) then
+			CU_PASS()
+		end if
+
+		CU_ASSERT( @T_static <> 0 )
+
+		if( @T_static = 0 ) then
+			CU_FAIL()
+		end if
+
+		if( @T_static <> 0 ) then
+			CU_PASS()
+		end if
+
+	END_TEST
+
+
+	TEST( compare_static_local )
 		dim as integer i1, i2
 		static as integer si1, si2