add the ability for TargetData to return information about legal integer

datatypes on a given CPU.  This is intended to allow instcombine and other
transformations to avoid converting big sequences of operations to an
inconvenient width, and will help clean up after SRoA.  See also "Adding 
legal integer sizes to TargetData" on Feb 1, 2009 on llvmdev, and PR3451.

Comments welcome.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86370 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 39 deletions

diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 06c493f..b6b84c5 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -139,45 +139,7 @@ static unsigned getInt(StringRef R) {
   return Result;
 }
 
-/*!
- A TargetDescription string consists of a sequence of hyphen-delimited
- specifiers for target endianness, pointer size and alignments, and various
- primitive type sizes and alignments. A typical string looks something like:
- <br><br>
- "E-p:32:32:32-i1:8:8-i8:8:8-i32:32:32-i64:32:64-f32:32:32-f64:32:64"
- <br><br>
- (note: this string is not fully specified and is only an example.)
- \p
- Alignments come in two flavors: ABI and preferred. ABI alignment (abi_align,
- below) dictates how a type will be aligned within an aggregate and when used
- as an argument.  Preferred alignment (pref_align, below) determines a type's
- alignment when emitted as a global.
- \p
- Specifier string details:
- <br><br>
- <i>[E|e]</i>: Endianness. "E" specifies a big-endian target data model, "e"
- specifies a little-endian target data model.
- <br><br>
- <i>p:@verbatim<size>:<abi_align>:<pref_align>@endverbatim</i>: Pointer size, 
- ABI and preferred alignment.
- <br><br>
- <i>@verbatim<type><size>:<abi_align>:<pref_align>@endverbatim</i>: Numeric type
- alignment. Type is
- one of <i>i|f|v|a</i>, corresponding to integer, floating point, vector, or
- aggregate.  Size indicates the size, e.g., 32 or 64 bits.
- \p
- The default string, fully specified, is:
- <br><br>
- "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64"
- "-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64"
- "-v64:64:64-v128:128:128"
- <br><br>
- Note that in the case of aggregates, 0 is the default ABI and preferred
- alignment. This is a special case, where the aggregate's computed worst-case
- alignment will be used.
- */ 
 void TargetData::init(StringRef Desc) {
-  
   LayoutMap = 0;
   LittleEndian = false;
   PointerMemSize = 8;
@@ -210,7 +172,7 @@ void TargetData::init(StringRef Desc) {
     
     assert(!Specifier.empty() && "Can't be empty here");
     
-    switch(Specifier[0]) {
+    switch (Specifier[0]) {
     case 'E':
       LittleEndian = false;
       break;
@@ -252,6 +214,17 @@ void TargetData::init(StringRef Desc) {
       setAlignment(AlignType, ABIAlign, PrefAlign, Size);
       break;
     }
+    case 'n':  // Native integer types.
+      Specifier = Specifier.substr(1);
+      do {
+        if (unsigned Width = getInt(Specifier))
+          LegalIntWidths.push_back(Width);
+        Split = Token.split(':');
+        Specifier = Split.first;
+        Token = Split.second;
+      } while (!Specifier.empty() || !Token.empty());
+      break;
+        
     default:
       break;
     }