iLoopVectorize: Non commutative operators can be used as reduction variables as long as the reduction chain is used in the LHS.

PR14803.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171583 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nadav Rotem
2013-01-05 01:15:47 +00:00
parent f7737b5baa
commit d5b92c3891
3 changed files with 44 additions and 7 deletions
@@ -241,7 +241,7 @@ define void @example8(i32 %x) nounwind uwtable ssp {
}
;CHECK: @example9
;CHECK-NOT: phi <4 x i32>
;CHECK: phi <4 x i32>
;CHECK: ret i32
define i32 @example9() nounwind uwtable readonly ssp {
br label %1
+30 -2
View File
@@ -296,11 +296,12 @@ for.end: ; preds = %for.body, %entry
ret i32 %x.0.lcssa
}
;CHECK: @reduction_sub_lhs
; In this code the subtracted variable is on the RHS and this is not an induction variable.
;CHECK: @reduction_sub_rhs
;CHECK-NOT: phi <4 x i32>
;CHECK-NOT: sub nsw <4 x i32>
;CHECK: ret i32
define i32 @reduction_sub_lhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
define i32 @reduction_sub_rhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
entry:
%cmp4 = icmp sgt i32 %n, 0
br i1 %cmp4, label %for.body, label %for.end
@@ -320,3 +321,30 @@ for.end: ; preds = %for.body, %entry
%x.0.lcssa = phi i32 [ 0, %entry ], [ %sub, %for.body ]
ret i32 %x.0.lcssa
}
; In this test the reduction variable is on the LHS and we can vectorize it.
;CHECK: @reduction_sub_lhs
;CHECK: phi <4 x i32>
;CHECK: sub nsw <4 x i32>
;CHECK: ret i32
define i32 @reduction_sub_lhs(i32 %n, i32* noalias nocapture %A) nounwind uwtable readonly {
entry:
%cmp4 = icmp sgt i32 %n, 0
br i1 %cmp4, label %for.body, label %for.end
for.body: ; preds = %entry, %for.body
%indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %entry ]
%x.05 = phi i32 [ %sub, %for.body ], [ 0, %entry ]
%arrayidx = getelementptr inbounds i32* %A, i64 %indvars.iv
%0 = load i32* %arrayidx, align 4
%sub = sub nsw i32 %x.05, %0
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp eq i32 %lftr.wideiv, %n
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %entry
%x.0.lcssa = phi i32 [ 0, %entry ], [ %sub, %for.body ]
ret i32 %x.0.lcssa
}