Use SmallVectorImpl::iterator/const_iterator instead of SmallVector to avoid specifyi...

[oota-llvm.git] / lib / Target / README.txt

diff --git a/lib/Target/README.txt b/lib/Target/README.txt
index 2d4925d307a5aee5cc6057519711d748193b8e03..a9aab86abdacb830e02f8c364723e8ed94f25541 100644 (file)
--- a/lib/Target/README.txt
+++ b/lib/Target/README.txt
@@ -2,22 +2,6 @@ Target Independent Opportunities:
 
 //===---------------------------------------------------------------------===//
 
 
 //===---------------------------------------------------------------------===//
 

-With the recent changes to make the implicit def/use set explicit in
-machineinstrs, we should change the target descriptions for 'call' instructions
-so that the .td files don't list all the call-clobbered registers as implicit
-defs.  Instead, these should be added by the code generator (e.g. on the dag).
-
-This has a number of uses:
-
-1. PPC32/64 and X86 32/64 can avoid having multiple copies of call instructions
-   for their different impdef sets.
-2. Targets with multiple calling convs (e.g. x86) which have different clobber
-   sets don't need copies of call instructions.
-3. 'Interprocedural register allocation' can be done to reduce the clobber sets
-   of calls.
-
-//===---------------------------------------------------------------------===//
-

 We should recognized various "overflow detection" idioms and translate them into
 llvm.uadd.with.overflow and similar intrinsics.  Here is a multiply idiom:
 
 We should recognized various "overflow detection" idioms and translate them into
 llvm.uadd.with.overflow and similar intrinsics.  Here is a multiply idiom:
 


@@ -168,7 +152,7 @@ stuff too.
 
 //===---------------------------------------------------------------------===//
 
 
 //===---------------------------------------------------------------------===//
 

-For vector types, TargetData.cpp::getTypeInfo() returns alignment that is equal
+For vector types, DataLayout.cpp::getTypeInfo() returns alignment that is equal

 to the type size. It works but can be overly conservative as the alignment of
 specific vector types are target dependent.
 
 to the type size. It works but can be overly conservative as the alignment of
 specific vector types are target dependent.
 


@@ -278,22 +262,7 @@ unsigned countbits_slow(unsigned v) {
     c += v & 1;
   return c;
 }
     c += v & 1;
   return c;
 }

-unsigned countbits_fast(unsigned v){
-  unsigned c;
-  for (c = 0; v; c++)
-    v &= v - 1; // clear the least significant bit set
-  return c;
-}

 
 

-BITBOARD = unsigned long long
-int PopCnt(register BITBOARD a) {
-  register int c=0;
-  while(a) {
-    c++;
-    a &= a - 1;
-  }
-  return c;
-}

 unsigned int popcount(unsigned int input) {
   unsigned int count = 0;
   for (unsigned int i =  0; i < 4 * 8; i++)
 unsigned int popcount(unsigned int input) {
   unsigned int count = 0;
   for (unsigned int i =  0; i < 4 * 8; i++)


@@ -973,6 +942,19 @@ optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
 
 //===---------------------------------------------------------------------===//
 
 
 //===---------------------------------------------------------------------===//
 

+int f(int i, int j) { return i < j + 1; }
+int g(int i, int j) { return j > i - 1; }
+Should combine to "i <= j" (the add/sub has nsw).  Currently not
+optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+
+//===---------------------------------------------------------------------===//
+
+unsigned f(unsigned x) { return ((x & 7) + 1) & 15; }
+The & 15 part should be optimized away, it doesn't change the result. Currently
+not optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+
+//===---------------------------------------------------------------------===//
+

 This was noticed in the entryblock for grokdeclarator in 403.gcc:
 
         %tmp = icmp eq i32 %decl_context, 4          
 This was noticed in the entryblock for grokdeclarator in 403.gcc:
 
         %tmp = icmp eq i32 %decl_context, 4