llvm-6502/test/Transforms/InstCombine/bitcount.ll
Chandler Carruth ddbc274169 Manually upgrade the test suite to specify the flag to cttz and ctlz.
I followed three heuristics for deciding whether to set 'true' or
'false':

- Everything target independent got 'true' as that is the expected
  common output of the GCC builtins.
- If the target arch only has one way of implementing this operation,
  set the flag in the way that exercises the most of codegen. For most
  architectures this is also the likely path from a GCC builtin, with
  'true' being set. It will (eventually) require lowering away that
  difference, and then lowering to the architecture's operation.
- Otherwise, set the flag differently dependending on which target
  operation should be tested.

Let me know if anyone has any issue with this pattern or would like
specific tests of another form. This should allow the x86 codegen to
just iteratively improve as I teach the backend how to differentiate
between the two forms, and everything else should remain exactly the
same.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146370 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-12 11:59:10 +00:00

20 lines
620 B
LLVM

; Tests to make sure bit counts of constants are folded
; RUN: opt < %s -instcombine -S | grep {ret i32 19}
; RUN: opt < %s -instcombine -S | \
; RUN: grep -v declare | not grep llvm.ct
declare i31 @llvm.ctpop.i31(i31 %val)
declare i32 @llvm.cttz.i32(i32 %val, i1)
declare i33 @llvm.ctlz.i33(i33 %val, i1)
define i32 @test(i32 %A) {
%c1 = call i31 @llvm.ctpop.i31(i31 12415124)
%c2 = call i32 @llvm.cttz.i32(i32 87359874, i1 true)
%c3 = call i33 @llvm.ctlz.i33(i33 87359874, i1 true)
%t1 = zext i31 %c1 to i32
%t3 = trunc i33 %c3 to i32
%r1 = add i32 %t1, %c2
%r2 = add i32 %r1, %t3
ret i32 %r2
}