[PATCH] PR modula2/115536 Expression is evaluated incorrectly when encountering relop...

[PATCH] PR modula2/115536 Expression is evaluated incorrectly when encountering relops and indirection

This fix ensures that we only call BuildRelOpFromBoolean if we are
inside a constant expression (where no indirection can be used).
The fix creates a temporary variable when a boolean is created from
a relop in other cases.
The previous pattern implementation would not work if the operands required
dereferencing during non const expressions.  Comparison of relop results
in a constant expression are resolved by constant propagation, basic
block analysis and dead code removal.  After the quadruples have been
optimized only one assignment to the boolean variable will remain for
const expressions.  All quadruple pattern checking for boolean
expressions is removed by the patch.  Thus the implementation becomes
more generic.

gcc/m2/ChangeLog:

	PR modula2/115536
	* gm2-compiler/M2BasicBlock.def (GetBasicBlockScope): New procedure.
	(GetBasicBlockStart): Ditto.
	(GetBasicBlockEnd): Ditto.
	(IsBasicBlockFirst): New procedure function.
	* gm2-compiler/M2BasicBlock.mod (ConvertQuads2BasicBlock): Allow
	conditional boolean quads to be removed.
	(GetBasicBlockScope): Implement new procedure.
	(GetBasicBlockStart): Ditto.
	(GetBasicBlockEnd): Ditto.
	(IsBasicBlockFirst): Implement new procedure function.
	* gm2-compiler/M2GCCDeclare.def (FoldConstants): New parameter
	declaration.
	* gm2-compiler/M2GCCDeclare.mod (FoldConstants): New parameter
	declaration.
	(DeclareTypesConstantsProceduresInRange): Recreate basic blocks
	after resolving constant expressions.
	(CodeBecomes): Guard IsVariableSSA with IsVar.
	* gm2-compiler/M2GenGCC.def (ResolveConstantExpressions): New
	parameter declaration.
	* gm2-compiler/M2GenGCC.mod (FoldIfLess): Remove relop pattern
	detection.
	(FoldIfGre): Ditto.
	(FoldIfLessEqu): Ditto.
	(FoldIfGreEqu): Ditto.
	(FoldIfIn): Ditto.
	(FoldIfNotIn): Ditto.
	(FoldIfEqu): Ditto.
	(FoldIfNotEqu): Ditto.
	(FoldBecomes): Add BasicBlock parameter and allow conditional
	boolean becomes to be folded in the first basic block.
	(ResolveConstantExpressions): Reimplement.
	* gm2-compiler/M2Quads.def (IsConstQuad): New procedure function.
	(IsConditionalBooleanQuad): Ditto.
	* gm2-compiler/M2Quads.mod (IsConstQuad): Implement new procedure function.
	(IsConditionalBooleanQuad): Ditto.
	(MoveWithMode): Use GenQuadOTypetok.
	(IsInitialisingConst): Rewrite using OpUsesOp1.
	(OpUsesOp1): New procedure function.
	(doBuildAssignment): Mark des as a VarConditional.
	(ConvertBooleanToVariable): Call PutVarConditional.
	(DumpQuadSummary): New procedure.
	(BuildRelOpFromBoolean): Updated debugging and improved comments.
	(BuildRelOp): Only call BuildRelOpFromBoolean if we are in a const
	expression and both operands are boolean relops.
	(GenQuadOTypeUniquetok): New procedure.
	(BackPatch): Correct comment.
	* gm2-compiler/SymbolTable.def (PutVarConditional): New procedure.
	(IsVarConditional): New procedure function.
	* gm2-compiler/SymbolTable.mod (PutVarConditional): Implement new
	procedure.
	(IsVarConditional): Implement new procedure function.
	(SymConstVar): New field IsConditional.
	(SymVar): New field IsConditional.
	(MakeVar): Initialize IsConditional field.
	(MakeConstVar): Initialize IsConditional field.
	* gm2-compiler/M2Swig.mod (DoBasicBlock): Change parameters to
	use BasicBlock.
	* gm2-compiler/M2Code.mod (SecondDeclareAndOptimize): Use iterator
	to FoldConstants over basic block list.
	* gm2-compiler/M2SymInit.mod (AppendEntry): Replace parameters
	with BasicBlock.
	* gm2-compiler/P3Build.bnf (Relation): Call RecordOp for #, <> and =.

gcc/testsuite/ChangeLog:

	PR modula2/115536
	* gm2/iso/const/pass/constbool4.mod: New test.
	* gm2/iso/const/pass/constbool5.mod: New test.
	* gm2/iso/run/pass/condtest2.mod: New test.
	* gm2/iso/run/pass/condtest3.mod: New test.
	* gm2/iso/run/pass/condtest4.mod: New test.
	* gm2/iso/run/pass/condtest5.mod: New test.
	* gm2/iso/run/pass/constbool4.mod: New test.

(cherry picked from commit 9f168b412f44781013401492acfedf22afe7741b)

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