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[SCEV] Add tests where guards limit both %n and (zext %n). 

Suggested in D113577.
This commit is contained in:
Florian Hahn 2021-11-12 10:30:03 +00:00
parent aa26119b82
commit 5dfe60d171
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1 changed files with 67 additions and 0 deletions

67
llvm/test/Analysis/ScalarEvolution/max-backedge-taken-count-guard-info-rewrite-expressions.ll
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@ -130,6 +130,73 @@ exit:
ret i32 0
}
; Make sure no information is lost for conditions on both %n and (zext %n).
define void @rewrite_zext_and_base_1(i32 %n) {
; CHECK-LABEL: Determining loop execution counts for: @rewrite_zext_and_base
; CHECK-NEXT: Loop %loop: backedge-taken count is ((-8 + (8 * ((zext i32 %n to i64) /u 8))<nuw><nsw>)<nsw> /u 8)
; CHECK-NEXT: Loop %loop: max backedge-taken count is 2305843009213693951
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is ((-8 + (8 * ((zext i32 %n to i64) /u 8))<nuw><nsw>)<nsw> /u 8)
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 1
;
entry:
%ext = zext i32 %n to i64
%cmp5 = icmp ule i64 %ext, 48
br i1 %cmp5, label %check.1, label %exit
check.1:
%cmp.2 = icmp ule i32 %n, 32
br i1 %cmp.2, label %check, label %exit
check: ; preds = %entry
%min.iters.check = icmp ult i64 %ext, 8
%n.vec = and i64 %ext, -8
br i1 %min.iters.check, label %exit, label %loop
loop:
%index = phi i64 [ 0, %check ], [ %index.next, %loop ]
%index.next = add nuw nsw i64 %index, 8
%ec = icmp eq i64 %index.next, %n.vec
br i1 %ec, label %exit, label %loop
exit:
ret void
}
; Make sure no information is lost for conditions on both %n and (zext %n).
define void @rewrite_zext_and_base_2(i32 %n) {
; CHECK-LABEL: Determining loop execution counts for: @rewrite_zext_and_base
; CHECK-NEXT: Loop %loop: backedge-taken count is ((-8 + (8 * ((zext i32 %n to i64) /u 8))<nuw><nsw>)<nsw> /u 8)
; CHECK-NEXT: Loop %loop: max backedge-taken count is 2305843009213693951
; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is ((-8 + (8 * ((zext i32 %n to i64) /u 8))<nuw><nsw>)<nsw> /u 8)
; CHECK-NEXT: Predicates:
; CHECK: Loop %loop: Trip multiple is 1
;
entry:
%ext = zext i32 %n to i64
%cmp5 = icmp ule i64 %ext, 32
br i1 %cmp5, label %check.1, label %exit
check.1:
%cmp.2 = icmp ule i32 %n, 48
br i1 %cmp.2, label %check, label %exit
check: ; preds = %entry
%min.iters.check = icmp ult i64 %ext, 8
%n.vec = and i64 %ext, -8
br i1 %min.iters.check, label %exit, label %loop
loop:
%index = phi i64 [ 0, %check ], [ %index.next, %loop ]
%index.next = add nuw nsw i64 %index, 8
%ec = icmp eq i64 %index.next, %n.vec
br i1 %ec, label %exit, label %loop
exit:
ret void
}
declare void @use(i64)
declare i32 @llvm.umin.i32(i32, i32)