llvm-6502/test/CodeGen/Thumb2/thumb2-ifcvt1.ll
Dan Gohman a10756ee65 Re-implement the main strength-reduction portion of LoopStrengthReduction.
This new version is much more aggressive about doing "full" reduction in
cases where it reduces register pressure, and also more aggressive about
rewriting induction variables to count down (or up) to zero when doing so
reduces register pressure.

It currently uses fairly simplistic algorithms for finding reuse
opportunities, but it introduces a new framework allows it to combine
multiple strategies at once to form hybrid solutions, instead of doing
all full-reduction or all base+index.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94061 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-21 02:09:26 +00:00

85 lines
2.4 KiB
LLVM

; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s
define i32 @t1(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
; CHECK: t1:
; CHECK: it ne
; CHECK: cmpne
switch i32 %c, label %cond_next [
i32 1, label %cond_true
i32 7, label %cond_true
]
cond_true:
%tmp12 = add i32 %a, 1
%tmp1518 = add i32 %tmp12, %b
ret i32 %tmp1518
cond_next:
%tmp15 = add i32 %b, %a
ret i32 %tmp15
}
; FIXME: Check for # of unconditional branch after adding branch folding post ifcvt.
define i32 @t2(i32 %a, i32 %b) nounwind {
entry:
; CHECK: t2:
; CHECK: ite gt
; CHECK: subgt
; CHECK: suble
%tmp1434 = icmp eq i32 %a, %b ; <i1> [#uses=1]
br i1 %tmp1434, label %bb17, label %bb.outer
bb.outer: ; preds = %cond_false, %entry
%b_addr.021.0.ph = phi i32 [ %b, %entry ], [ %tmp10, %cond_false ] ; <i32> [#uses=5]
%a_addr.026.0.ph = phi i32 [ %a, %entry ], [ %a_addr.026.0, %cond_false ] ; <i32> [#uses=1]
br label %bb
bb: ; preds = %cond_true, %bb.outer
%indvar = phi i32 [ 0, %bb.outer ], [ %indvar.next, %cond_true ] ; <i32> [#uses=2]
%tmp. = sub i32 0, %b_addr.021.0.ph ; <i32> [#uses=1]
%tmp.40 = mul i32 %indvar, %tmp. ; <i32> [#uses=1]
%a_addr.026.0 = add i32 %tmp.40, %a_addr.026.0.ph ; <i32> [#uses=6]
%tmp3 = icmp sgt i32 %a_addr.026.0, %b_addr.021.0.ph ; <i1> [#uses=1]
br i1 %tmp3, label %cond_true, label %cond_false
cond_true: ; preds = %bb
%tmp7 = sub i32 %a_addr.026.0, %b_addr.021.0.ph ; <i32> [#uses=2]
%tmp1437 = icmp eq i32 %tmp7, %b_addr.021.0.ph ; <i1> [#uses=1]
%indvar.next = add i32 %indvar, 1 ; <i32> [#uses=1]
br i1 %tmp1437, label %bb17, label %bb
cond_false: ; preds = %bb
%tmp10 = sub i32 %b_addr.021.0.ph, %a_addr.026.0 ; <i32> [#uses=2]
%tmp14 = icmp eq i32 %a_addr.026.0, %tmp10 ; <i1> [#uses=1]
br i1 %tmp14, label %bb17, label %bb.outer
bb17: ; preds = %cond_false, %cond_true, %entry
%a_addr.026.1 = phi i32 [ %a, %entry ], [ %tmp7, %cond_true ], [ %a_addr.026.0, %cond_false ] ; <i32> [#uses=1]
ret i32 %a_addr.026.1
}
@x = external global i32* ; <i32**> [#uses=1]
define void @foo(i32 %a) nounwind {
entry:
%tmp = load i32** @x ; <i32*> [#uses=1]
store i32 %a, i32* %tmp
ret void
}
define void @t3(i32 %a, i32 %b) nounwind {
entry:
; CHECK: t3:
; CHECK: it lt
; CHECK: poplt {r7, pc}
%tmp1 = icmp sgt i32 %a, 10 ; <i1> [#uses=1]
br i1 %tmp1, label %cond_true, label %UnifiedReturnBlock
cond_true: ; preds = %entry
tail call void @foo( i32 %b )
ret void
UnifiedReturnBlock: ; preds = %entry
ret void
}