First, it allows SRA of globals that have embedded arrays, implementing
GlobalOpt/globalsra-partial.llx. This comes up infrequently, but does allow,
for example, deleting several stores to dead parts of globals in dhrystone.
Second, this implements GlobalOpt/malloc-promote-*.llx, which is the
following nifty transformation:
Basically if a global pointer is initialized with malloc, and we can tell
that the program won't notice, we transform this:
struct foo *FooPtr;
...
FooPtr = malloc(sizeof(struct foo));
...
FooPtr->A FooPtr->B
Into:
struct foo FooPtrBody;
...
FooPtrBody.A FooPtrBody.B
This comes up occasionally, for example, the 'disp' global in 183.equake (where
the xform speeds the CBE version of the program up from 56.16s to 52.40s (7%)
on apoc), and the 'desired_accept', 'fixLRBT', 'macroArray', & 'key_queue'
globals in 300.twolf (speeding it up from 22.29s to 21.55s (3.4%)).
The nice thing about this xform is that it exposes the resulting global to
global variable optimization and makes alias analysis easier in addition to
eliminating a few loads.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16916 91177308-0d34-0410-b5e6-96231b3b80d8
first element of an array, return a GEP instead of a cast. This allows us
to transparently fold this:
int* getelementptr (int* cast ([100 x int]* %Gbody to int*), int 40)
into this:
int* getelementptr ([100 x int]* %Gbody, int 0, int 40)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16911 91177308-0d34-0410-b5e6-96231b3b80d8
still optimize away all of the indirect calls and loads, etc from it.
This turns code like this:
if (G != 0)
G();
into
if (G != 0)
ActualCallee();
This triggers a couple of times in gcc and libstdc++.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16901 91177308-0d34-0410-b5e6-96231b3b80d8
argument values passed in (so they're not dead until *after* the call),
and callees are free to modify those registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16882 91177308-0d34-0410-b5e6-96231b3b80d8
Deal with allocating stack space for outgoing args and copying them into the
correct stack slots (at least, we can copy <=32-bit int args).
We now correctly generate ADJCALLSTACK* instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16881 91177308-0d34-0410-b5e6-96231b3b80d8
stored to, but are stored at variable indexes. This occurs at least in
176.gcc, but probably others, and we should handle it for completeness.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16876 91177308-0d34-0410-b5e6-96231b3b80d8
has a large number of users. Instead, just keep track of whether we're
making changes as we do so.
This patch has no functionlity changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16874 91177308-0d34-0410-b5e6-96231b3b80d8
we know that all uses of the global will trap if the pointer contained is
null. In this case, we forward substitute the stored value to any uses.
This has the effect of devirtualizing trivial globals in trivial cases. For
example, 164.gzip contains this:
gzip.h:extern int (*read_buf) OF((char *buf, unsigned size));
bits.c: read_buf = file_read;
deflate.c: lookahead = read_buf((char*)window,
deflate.c: n = read_buf((char*)window+strstart+lookahead, more);
Since read_buf has to point to file_read at every use, we just replace
the calls through read_buf with a direct call to file_read.
This occurs in several benchmarks, including 176.gcc and 164.gzip. Direct
calls are good and stuff.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16871 91177308-0d34-0410-b5e6-96231b3b80d8
