[RFC][IPA-VRP] IPA VRP Implementation

[kugan <kugan.vivekanandarajah@linaro.org>]

Hi,



This patch series implements IPA-VRP based on the previous discussions 
in https://gcc.gnu.org/ml/gcc/2016-01/msg00063.html.



0001-Hack-Prevent-setting-__builtin_constant_p-of-param-t.patch -This is 
to prevent EVRP setting result of __builtin_constant_p to null that will 
inlined later.



0002-Inliner-Check-for-POINTER_TYPE.patch - This is to make sure that we 
call SSA_NAME_PTR_INFO only for POINTER_TYPE_P. This is exposed with 
IPA-VRP but not related to rest of the patch.



0003-Refactor-vrp.patch - Re-factors tree-vrp to expose some of the 
common functionalities.

0004-Add-early-vrp.patch - Adds a simple Early VRP pass.

0005-Add-ipa-vrp.patch - Implements IPA VRP

0006-Teach-tree-vrp-to-use-ipa-vrp-results.patch - Teaches tree-vrp to 
use the value ranges set for the PARMs.



More details about the patches are later with each patch.



Before I go into the details, here is a simple example and the relevant 
dumps as of now:



static __attribute__((noinline, noclone))

int foo (int i)

{

   if (i > 5)

     printf ("OK\n");

   else

     printf ("NOK\n");

}



int bar (int j)

{

   if (j > 8)

     return foo (j + 2);

   else if (j > 2)

     return foo (j + 3);



   return 0;

}





The Early VRP dump shows:



_1: [11, +INF(OVF)]

_2: [6, 11]

....



bar (int j)

{

....

   _8 = foo (_1);

   goto <bb 6>;



   <bb 4>:

   if (j_5(D) > 2)

     goto <bb 5>;

   else

     goto <bb 6>;



   <bb 5>:

   _2 = j_5(D) + 3;

   _10 = foo (_2);



....




The IPA-CP dump shows:

....

Modification phase of node foo/0

Setting value range of param 0 [6, 2147483647]

__attribute__((noclone, noinline))

foo (int i)

....





The VRP1 dump shows:



Value ranges after VRP:



.MEM_1: VARYING

i_2(D): [6, +INF]





Folding predicate i_2(D) > 5 to 1

Removing basic block 4

Merging blocks 2 and 3

Merging blocks 2 and 5

__attribute__((noclone, noinline))

foo (int i)

{

   <bb 2>:

   __builtin_puts (&"OK"[0]);

   return;



}



I have bootstrapped and regression tested the patches in this series on 
x86-64 and aarch64 (both normal bootstrap and LTO bootstrap).

There are couple of testcase failures which I am looking into.



Any thoughts?



Thanks,

Kugan