JIT: Model GetFfr* with a special side effect and handle it in VN

[jakobbotsch]

• Add HW_Flag_SpecialSideEffect_Other to GetFfr* HW intrinsics. These intrinsics essentially read memory from memory that we do not model, so we have to treat them conservatively.
• Add GTF_CALL and GTF_GLOB_REF to GetFfr* HW intrinsics. We have to give these a conservative set of a flag to disallow the rest of the JIT from potentially reordering them with SetFfr.
• Teach VN to give all HW intrinsics with any special side effect a unique VN

Fix #105944

In the test case head-merging reorders a SetFfr with a GetFfr since GetFfr is not given appropriately conservative side effect flags:

*************** Starting PHASE Head and tail merge
Both succs of BB01 start with the same tree
STMT00006 ( 0x02F[E-] ... 0x03C )
               [000039] --C-G------                         *  HWINTRINSIC void   ubyte SetFfr
               [000037] -----------                         \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000036] -----------                            \--*  CNS_INT   int    31
Checking if we can move it into the predecessor...
We can; moving statement

unlinking STMT00006 ( 0x02F[E-] ... 0x03C )
               [000039] --C-G------                         *  HWINTRINSIC void   ubyte SetFfr
               [000037] -----------                         \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000036] -----------                            \--*  CNS_INT   int    31
 from BB02

unlinking STMT00004 ( 0x03D[E-] ... 0x04A )
               [000031] --C-G------                         *  HWINTRINSIC void   ubyte SetFfr
               [000029] -----------                         \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000028] -----------                            \--*  CNS_INT   int    31
 from BB03
Did 1 head merges in BB01
...
------------ BB01 [0000] [000..02F) -> BB03(0.5),BB02(0.5) (cond), preds={} succs={BB02,BB03}

***** BB01 [0000]
STMT00000 ( 0x000[E-] ... 0x01B )
               [000003] --C-G------                         *  HWINTRINSIC void   ubyte SetFfr
               [000001] -----------                         \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000000] -----------                            \--*  CNS_INT   int    31

***** BB01 [0000]
STMT00001 ( 0x00C[E-] ... ??? )
               [000016] DA-XG------                         *  STORE_LCL_VAR simd16 V02 tmp1         
               [000013] ---XG------                         \--*  HWINTRINSIC simd16 ubyte LoadVectorFirstFaulting
               [000015] -----------                            +--*  HWINTRINSIC mask   ubyte ConvertVectorToMask
               [000014] -----------                            |  +--*  HWINTRINSIC mask   ubyte CreateTrueMaskAll
               [000008] -----------                            |  \--*  HWINTRINSIC simd16 ubyte ConvertMaskToVector
               [000007] -----------                            |     \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000006] -----------                            |        \--*  CNS_INT   int    31
               [000012] -----------                            \--*  ADD       long  
               [000009] -----------                               +--*  LCL_VAR   long   V00 arg0         
               [000011] -----------                               \--*  CAST      long <- int
               [000010] -----------                                  \--*  CNS_INT   int    1

***** BB01 [0000]
STMT00002 ( ??? ... ??? )
               [000018] -----------                         *  NOP       void  

***** BB01 [0000]
STMT00006 ( 0x02F[E-] ... 0x03C )
               [000039] --C-G------                         *  HWINTRINSIC void   ubyte SetFfr                                ; head-merging moved this from the then/else blocks
               [000037] -----------                         \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000036] -----------                            \--*  CNS_INT   int    31

***** BB01 [0000]
STMT00003 ( 0x01C[E-] ... 0x02D )
               [000027] -----------                         *  JTRUE     void  
               [000026] -----------                         \--*  EQ        int   
               [000024] -----------                            +--*  HWINTRINSIC int    ubyte op_Equality
               [000020] -----------                            |  +--*  HWINTRINSIC simd16 ubyte ConvertMaskToVector
               [000019] -----------                            |  |  \--*  HWINTRINSIC mask   ubyte GetFfrByte
               [000023] -----------                            |  \--*  HWINTRINSIC simd16 ubyte ConvertMaskToVector
               [000022] -----------                            |     \--*  HWINTRINSIC mask   ubyte CreateTrueMaskByte
               [000021] -----------                            |        \--*  CNS_INT   int    31
               [000025] -----------                            \--*  CNS_INT   int    0

[jakobbotsch]

cc @dotnet/jit-contrib PTAL @kunalspathak @TIHan @amanasifkhalid

[jakobbotsch]

No diffs