//===---------------------------------------------------------------------===//
-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:
//===---------------------------------------------------------------------===//
-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.
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++)
//===---------------------------------------------------------------------===//
+int g(int x) { return (x - 10) < 0; }
+Should combine to "x <= 9" (the sub has nsw). Currently not
+optimized with "clang -emit-llvm-bc | opt -std-compile-opts".
+
+//===---------------------------------------------------------------------===//
+
+int g(int x) { return (x + 10) < 0; }
+Should combine to "x < -10" (the add has nsw). Currently not
+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
probably best to do this in the code generator.
//===---------------------------------------------------------------------===//
+
+unsigned foo(unsigned x, unsigned y) { return (x & y) == 0 || x == 0; }
+should fold to (x & y) == 0.
+
+//===---------------------------------------------------------------------===//
+
+unsigned foo(unsigned x, unsigned y) { return x > y && x != 0; }
+should fold to x > y.
+
+//===---------------------------------------------------------------------===//