JIT should eliminate useless comparisons against int.MaxValue / nint.MaxValue / long.MaxValue

[GrabYourPitchforks]

(Related to but distinct from #37462.)

Repro code

public static bool M(int x) {
    return (x > int.MaxValue);
}

M(Int32)
    L0000: cmp ecx, 0x7fffffff
    L0006: setg al
    L0009: movzx eax, al
    L000c: ret

Discussion

When comparing an int against int.MaxValue, or a uint against uint.MaxValue, or an nint against nint.MaxValue, etc., the JIT should eliminate comparisons that it knows will always evaluate to a constant true or false value.

This can help simplify code like the following, where line 136 below can be replaced with a simple if (bytesAllocated > nint.MaxValue), with the JIT eliminating the branch entirely if it knows the branch can never possibly be taken.

runtime/src/coreclr/System.Private.CoreLib/src/System/GC.cs

Lines 128 to 143 in e6bb456

	public static void AddMemoryPressure(long bytesAllocated)
	{
	if (bytesAllocated <= 0)
	{
	throw new ArgumentOutOfRangeException(nameof(bytesAllocated),
	SR.ArgumentOutOfRange_NeedPosNum);
	}
	if ((4 == IntPtr.Size) && (bytesAllocated > int.MaxValue))
	{
	throw new ArgumentOutOfRangeException(nameof(bytesAllocated),
	SR.ArgumentOutOfRange_MustBeNonNegInt32);
	}
	_AddMemoryPressure((ulong)bytesAllocated);
	}

category:cq
theme:type-intrinsics
skill-level:beginner
cost:small
impact:small

[EgorBo]

The easiest fix is to recognize & optimize:

*  GT        int   
+--*  CAST      long <- int
|  \--*  LCL_VAR   int      
\--*  CNS_INT   long   0x7FFFFFFF

But it won't help with the AddMemoryPressure where it's more like:

*  ASG       long  
+--*  LCL_VAR   long   V02 tmp1         
\--*  CAST      long <- int
   \--*  LCL_VAR   int    V00 arg0         

*  JTRUE     void  
\--*  LE        int   
   +--*  LCL_VAR   long   V02 tmp1         
   \--*  CNS_INT   long   0x7FFFFFFF

[SingleAccretion]

Global morph already performs local assertion propagation. I wonder if we can leverage that here.