PR modula2/120117: ICE when attempting to obtain the MAX of an aliased set type

The ICE occurred because of a bug in M2GenGCC.mod:FoldBecomes which
attempted to remove the same quadruple twice.  Thereafter cc1gm2
generated an erroneous error type error as PCSymBuild did not skip
an aliased set type.  The type of the const was set incorrectly
(as a set type) rather than the type of the set element.

gcc/m2/ChangeLog:

	PR modula2/120117
	* gm2-compiler/M2GenGCC.mod (FoldBecomes): Remove the call to
	RemoveQuad since this is performed by TypeCheckBecomes.
	* gm2-compiler/PCSymBuild.mod (buildConstFunction): Rewrite
	header comment.
	Check for a set or a type aliased set and appropriately
	skip type equivalences and obtain the element type.
	* gm2-compiler/SymbolTable.mod (PutConst): Add call to
	CheckBreak.

gcc/testsuite/ChangeLog:

	PR modula2/120117
	* gm2/pim/pass/highbit.mod: New test.
	* gm2/pim/pass/highbit2.mod: New test.

Signed-off-by: Gaius Mulley <gaiusmod2@gmail.com>

5 files changed, 34 insertions, 9 deletions

diff --git a/gcc/m2/gm2-compiler/M2GenGCC.mod b/gcc/m2/gm2-compiler/M2GenGCC.mod
index a1e3c07..bc1d588 100644
--- a/gcc/m2/gm2-compiler/M2GenGCC.mod
+++ b/gcc/m2/gm2-compiler/M2GenGCC.mod
@@ -2914,9 +2914,6 @@ BEGIN
          IF TypeCheckBecomes (p, quad)
          THEN
             PerformFoldBecomes (p, quad)
-         ELSE
-            GetQuad (quad, op, des, op2, expr) ;
-            RemoveQuad (p, des, quad)
          END
       END
    END
diff --git a/gcc/m2/gm2-compiler/PCSymBuild.mod b/gcc/m2/gm2-compiler/PCSymBuild.mod
index b124c3e..3bffe86 100644
--- a/gcc/m2/gm2-compiler/PCSymBuild.mod
+++ b/gcc/m2/gm2-compiler/PCSymBuild.mod
@@ -64,7 +64,7 @@ FROM SymbolTable IMPORT NulSym, ModeOfAddr, ProcedureKind,
                         GetFromOuterModule,
                         CheckForEnumerationInCurrentModule,
                         GetMode, PutVariableAtAddress, ModeOfAddr, SkipType,
-                        IsSet, PutConstSet,
+                        IsSet, PutConstSet, IsType,
                         IsConst, IsConstructor, PutConst, PutConstructor,
                         PopValue, PushValue,
                         MakeTemporary, PutVar,
@@ -1408,9 +1408,10 @@ END TypeToMeta ;
 
 
 (*
-   buildConstFunction - we are only concerned about resolving the return type o
+   buildConstFunction - we are only concerned about resolving the return type of
                         a function, so we can ignore all parameters - except
-                        the first one in the case of VAL(type, foo).
+                        the first one in the case of VAL(type, foo)
+                        and the type of bar in MIN (bar) and MAX (bar).
                         buildConstFunction uses a unary exprNode to represent
                         a function.
 *)
@@ -1866,11 +1867,11 @@ BEGIN
             THEN
                IF (func=Min) OR (func=Max)
                THEN
-                  IF IsSet (sym)
+                  IF IsSet (sym) OR (IsType (sym) AND IsSet (SkipType (sym)))
                   THEN
-                     type := SkipType(GetType(sym))
+                     type := GetType (SkipType (sym))
                   ELSE
-                     (* sym is the type required for MAX, MIN and VAL *)
+                     (* sym is the type required for MAX, MIN and VAL.  *)
                      type := sym
                   END
                ELSE
diff --git a/gcc/m2/gm2-compiler/SymbolTable.mod b/gcc/m2/gm2-compiler/SymbolTable.mod
index 551bbec..ff661dc 100644
--- a/gcc/m2/gm2-compiler/SymbolTable.mod
+++ b/gcc/m2/gm2-compiler/SymbolTable.mod
@@ -7265,6 +7265,7 @@ VAR
    pSym: PtrToSymbol ;
 BEGIN
    pSym := GetPsym(Sym) ;
+   CheckBreak (Sym) ;
    WITH pSym^ DO
       CASE SymbolType OF
 
diff --git a/gcc/testsuite/gm2/pim/pass/highbit.mod b/gcc/testsuite/gm2/pim/pass/highbit.mod
new file mode 100644
index 0000000..c9c872a
--- /dev/null
+++ b/gcc/testsuite/gm2/pim/pass/highbit.mod
@@ -0,0 +1,13 @@
+MODULE highbit ;
+
+FROM libc IMPORT printf ;
+
+TYPE
+   set = BITSET ;
+
+CONST
+   HighBit = MAX (set) ;
+
+BEGIN
+   printf ("the MAX (set) = %d\n", HighBit)
+END highbit.
diff --git a/gcc/testsuite/gm2/pim/pass/highbit2.mod b/gcc/testsuite/gm2/pim/pass/highbit2.mod
new file mode 100644
index 0000000..940556d
--- /dev/null
+++ b/gcc/testsuite/gm2/pim/pass/highbit2.mod
@@ -0,0 +1,13 @@
+MODULE highbit2 ;
+
+FROM libc IMPORT printf ;
+
+TYPE
+   set = BITSET ;
+
+CONST
+   HighBit = MAX (BITSET) ;
+
+BEGIN
+   printf ("the MAX (BITSET) = %d\n", HighBit)
+END highbit2.