Adding a width of the GEP index to the Data Layout.

Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.

Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html

I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.

Differential Revision: https://reviews.llvm.org/D42123

llvm-svn: 325102

1 files changed, 24 insertions, 23 deletions

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index c560702f42f..965cdd4187f 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -1065,7 +1065,7 @@ Currently, only the following parameter attributes are defined:
     for return values.
 
 .. _attr_align:
-    
+
 ``align <n>``
     This indicates that the pointer value may be assumed by the optimizer to
     have the specified alignment.
@@ -1908,10 +1908,12 @@ as follows:
 ``A<address space>``
     Specifies the address space of  objects created by '``alloca``'.
     Defaults to the default address space of 0.
-``p[n]:<size>:<abi>:<pref>``
+``p[n]:<size>:<abi>:<pref>:<idx>``
     This specifies the *size* of a pointer and its ``<abi>`` and
-    ``<pref>``\erred alignments for address space ``n``. All sizes are in
-    bits. The address space, ``n``, is optional, and if not specified,
+    ``<pref>``\erred alignments for address space ``n``. The fourth parameter
+    ``<idx>`` is a size of index that used for address calculation. If not
+    specified, the default index size is equal to the pointer size. All sizes
+    are in bits. The address space, ``n``, is optional, and if not specified,
     denotes the default address space 0. The value of ``n`` must be
     in the range [1,2^23).
 ``i<size>:<abi>:<pref>``
@@ -2281,7 +2283,7 @@ Fast-Math Flags
 LLVM IR floating-point operations (:ref:`fadd <i_fadd>`,
 :ref:`fsub <i_fsub>`, :ref:`fmul <i_fmul>`, :ref:`fdiv <i_fdiv>`,
 :ref:`frem <i_frem>`, :ref:`fcmp <i_fcmp>`) and :ref:`call <i_call>`
-may use the following flags to enable otherwise unsafe 
+may use the following flags to enable otherwise unsafe
 floating-point transformations.
 
 ``nnan``
@@ -2308,11 +2310,11 @@ floating-point transformations.
 
 ``afn``
    Approximate functions - Allow substitution of approximate calculations for
-   functions (sin, log, sqrt, etc). See floating-point intrinsic definitions 
-   for places where this can apply to LLVM's intrinsic math functions. 
+   functions (sin, log, sqrt, etc). See floating-point intrinsic definitions
+   for places where this can apply to LLVM's intrinsic math functions.
 
 ``reassoc``
-   Allow reassociation transformations for floating-point instructions. 
+   Allow reassociation transformations for floating-point instructions.
    This may dramatically change results in floating point.
 
 ``fast``
@@ -6853,10 +6855,10 @@ Both arguments must have identical types.
 Semantics:
 """"""""""
 
-Return the same value as a libm '``fmod``' function but without trapping or 
+Return the same value as a libm '``fmod``' function but without trapping or
 setting ``errno``.
 
-The remainder has the same sign as the dividend. This instruction can also 
+The remainder has the same sign as the dividend. This instruction can also
 take any number of :ref:`fast-math flags <fastmath>`, which are optimization
 hints to enable otherwise unsafe floating-point optimizations:
 
@@ -10504,7 +10506,7 @@ Semantics:
 """"""""""
 
 The '``llvm.memset.*``' intrinsics fill "len" bytes of memory starting
-at the destination location. 
+at the destination location.
 
 '``llvm.sqrt.*``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -10538,10 +10540,10 @@ Semantics:
 """"""""""
 
 Return the same value as a corresponding libm '``sqrt``' function but without
-trapping or setting ``errno``. For types specified by IEEE-754, the result 
+trapping or setting ``errno``. For types specified by IEEE-754, the result
 matches a conforming libm implementation.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.powi.*``' Intrinsic
@@ -10616,7 +10618,7 @@ Semantics:
 Return the same value as a corresponding libm '``sin``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.cos.*``' Intrinsic
@@ -10653,7 +10655,7 @@ Semantics:
 Return the same value as a corresponding libm '``cos``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.pow.*``' Intrinsic
@@ -10691,7 +10693,7 @@ Semantics:
 Return the same value as a corresponding libm '``pow``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.exp.*``' Intrinsic
@@ -10729,7 +10731,7 @@ Semantics:
 Return the same value as a corresponding libm '``exp``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.exp2.*``' Intrinsic
@@ -10767,7 +10769,7 @@ Semantics:
 Return the same value as a corresponding libm '``exp2``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.log.*``' Intrinsic
@@ -10805,7 +10807,7 @@ Semantics:
 Return the same value as a corresponding libm '``log``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.log10.*``' Intrinsic
@@ -10843,7 +10845,7 @@ Semantics:
 Return the same value as a corresponding libm '``log10``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.log2.*``' Intrinsic
@@ -10881,7 +10883,7 @@ Semantics:
 Return the same value as a corresponding libm '``log2``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.fma.*``' Intrinsic
@@ -10918,7 +10920,7 @@ Semantics:
 Return the same value as a corresponding libm '``fma``' function but without
 trapping or setting ``errno``.
 
-When specified with the fast-math-flag 'afn', the result may be approximated 
+When specified with the fast-math-flag 'afn', the result may be approximated
 using a less accurate calculation.
 
 '``llvm.fabs.*``' Intrinsic
@@ -14558,4 +14560,3 @@ lowered to a call to the symbol ``__llvm_memset_element_unordered_atomic_*``. Wh
 is replaced with an actual element size.
 
 The optimizer is allowed to inline the memory assignment when it's profitable to do so.
-