llvm/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
Chandler Carruth 3d1a470319 [PM] Significantly refactor the pass pipeline parsing to be easier to
reason about and less error prone.

The core idea is to fully parse the text without trying to identify
passes or structure. This is done with a single state machine. There
were various bugs in the logic around this previously that were repeated
and scattered across the code. Having a single routine makes it much
easier to fix and get correct. For example, this routine doesn't suffer
from PR28577.

Then the actual pass construction is handled using *much* easier to read
code and simple loops, with particular pass manager construction sunk to
live with other pass construction. This is especially nice as the pass
managers *are* in fact passes.

Finally, the "implicit" pass manager synthesis is done much more simply
by forming "pre-parsed" structures rather than having to duplicate tons
of logic.

One of the bugs fixed by this was evident in the tests where we accepted
a pipeline that wasn't really well formed. Another bug is PR28577 for
which I have added a test case.

The code is less efficient than the previous code but I'm really hoping
that's not a priority. ;]

Thanks to Sean for the review!

Differential Revision: https://reviews.llvm.org/D22724

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277561 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-03 03:21:41 +00:00

55 lines
1.5 KiB
LLVM

; RUN: opt < %s -analyze -iv-users | FileCheck %s
; RUN: opt -passes='function(require<scalar-evolution>,loop(print<ivusers>))' -S < %s 2>&1| FileCheck %s
; Provide legal integer types.
target datalayout = "n8:16:32:64"
; The value of %r is dependent on a polynomial iteration expression.
;
; CHECK-LABEL: IV Users for loop %foo.loop
; CHECK: {1,+,3,+,2}<%foo.loop>
define i64 @foo(i64 %n) {
entry:
br label %foo.loop
foo.loop:
%indvar = phi i64 [ 0, %entry ], [ %indvar.next, %foo.loop ]
%indvar.next = add i64 %indvar, 1
%c = icmp eq i64 %indvar.next, %n
br i1 %c, label %exit, label %foo.loop
exit:
%r = mul i64 %indvar.next, %indvar.next
ret i64 %r
}
; PR15470: LSR miscompile. The test2 function should return '1'.
;
; SCEV does not know how to denormalize chained recurrences, so make
; sure they aren't marked as post-inc users.
;
; CHECK-LABEL: IV Users for loop %test2.loop
; CHECK: %sext.us = {0,+,(16777216 + (-16777216 * %sub.us))<nuw><nsw>,+,33554432}<%test2.loop> in %f = ashr i32 %sext.us, 24
define i32 @test2() {
entry:
br label %test2.loop
test2.loop:
%inc1115.us = phi i32 [ 0, %entry ], [ %inc11.us, %test2.loop ]
%inc11.us = add nsw i32 %inc1115.us, 1
%cmp.us = icmp slt i32 %inc11.us, 2
br i1 %cmp.us, label %test2.loop, label %for.end
for.end:
%tobool.us = icmp eq i32 %inc1115.us, 0
%sub.us = select i1 %tobool.us, i32 0, i32 0
%mul.us = shl i32 %inc1115.us, 24
%sub.cond.us = sub nsw i32 %inc1115.us, %sub.us
%sext.us = mul i32 %mul.us, %sub.cond.us
%f = ashr i32 %sext.us, 24
br label %exit
exit:
ret i32 %f
}