Add new micro-optimizations.
Add icmp predicate snuggling. Given %x ULT 4, "icmp ugt %x, 2" becomes
"icmp eq %x, 3". This doesn't apply in any non-trivial cases yet due to missing
support for NE values in ValueRanges.
llvm-svn: 35119
1. Replace getSignedMinValue() with getSignBit() for better code readability.
2. Replace APIntOps::shl() with operator<<= for convenience.
3. Make APInt construction more effective.
llvm-svn: 35060
Provide an APIntified version of MaskedValueIsZero. This will (temporarily)
cause a "defined but not used" message from the compiler. It will be used
in the next patch in this series.
Patch by Sheng Zhou.
llvm-svn: 35019
Add a new ComputeMaskedBits function that is APIntified. We'll slowly
convert things over to use this version. When its all done, we'll remove
the existing version.
llvm-svn: 35018
scalarrepl things down to elements, but mem2reg can't promote elements that
are memset/memcpy'd. Until then, the code is disabled "0 &&".
llvm-svn: 34924
would scan the entire loop body, then scan all users of instructions in the
loop, looking for users outside the loop. Now, since we know that the
loop is in LCSSA form, we know that any users outside the loop will be LCSSA
phi nodes. Just scan them.
This speeds up indvars significantly.
llvm-svn: 34898
the order that instcombine processed instructions in the testcase. The end
result is that instcombine finished with:
define i16 @test1(i16 %a) {
%tmp = zext i16 %a to i32 ; <i32> [#uses=2]
%tmp21 = lshr i32 %tmp, 8 ; <i32> [#uses=1]
%tmp5 = shl i32 %tmp, 8 ; <i32> [#uses=1]
%tmp.upgrd.32 = or i32 %tmp21, %tmp5 ; <i32> [#uses=1]
%tmp.upgrd.3 = trunc i32 %tmp.upgrd.32 to i16 ; <i16> [#uses=1]
ret i16 %tmp.upgrd.3
}
which can't get matched as a bswap.
This patch makes instcombine more sophisticated about removing truncating
casts, allowing it to turn this into:
define i16 @test2(i16 %a) {
%tmp211 = lshr i16 %a, 8
%tmp52 = shl i16 %a, 8
%tmp.upgrd.323 = or i16 %tmp211, %tmp52
ret i16 %tmp.upgrd.323
}
which then matches as bswap. This fixes bswap.ll and implements
InstCombine/cast2.ll:test[12]. This also implements cast elimination of
add/sub.
llvm-svn: 34870
a value from the worklist required scanning the entire worklist to remove all
entries. We now use a combination map+vector to prevent duplicates from
happening and prevent the scan. This speeds up instcombine on a large file
from the llvm-gcc bootstrap from 189.7s to 4.84s in a debug build and from
5.04s to 1.37s in a release build.
llvm-svn: 34848
