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| ; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
; An example run where SCEV(%postinc)->getStart() may overflow:
;
; %start = INT_SMAX
; %low.limit = INT_SMIN
; %high.limit = < not used >
;
; >> entry:
; %postinc.start = INT_SMIN
;
; >> loop:
; %idx = %start
; %postinc = INT_SMIN
; %postinc.inc = INT_SMIN + 1
; %postinc.sext = sext(INT_SMIN) = i64 INT32_SMIN
; %break.early = INT_SMIN `slt` INT_SMIN = false
; br i1 false, ___, %early.exit
;
; >> early.exit:
; ret i64 INT32_SMIN
define i64 @bad.0(i32 %start, i32 %low.limit, i32 %high.limit) {
; CHECK-LABEL: Classifying expressions for: @bad.0
entry:
%postinc.start = add i32 %start, 1
br label %loop
loop:
%idx = phi i32 [ %start, %entry ], [ %idx.inc, %continue ]
%postinc = phi i32 [ %postinc.start, %entry ], [ %postinc.inc, %continue ]
%postinc.inc = add nsw i32 %postinc, 1
%postinc.sext = sext i32 %postinc to i64
; CHECK: %postinc.sext = sext i32 %postinc to i64
; CHECK-NEXT: --> {(sext i32 (1 + %start) to i64),+,1}<nsw><%loop>
%break.early = icmp slt i32 %postinc, %low.limit
br i1 %break.early, label %continue, label %early.exit
continue:
%idx.inc = add nsw i32 %idx, 1
%cmp = icmp slt i32 %idx.inc, %high.limit
br i1 %cmp, label %loop, label %exit
exit:
ret i64 0
early.exit:
ret i64 %postinc.sext
}
define i64 @bad.1(i32 %start, i32 %low.limit, i32 %high.limit, i1* %unknown) {
; CHECK-LABEL: Classifying expressions for: @bad.1
entry:
%postinc.start = add i32 %start, 1
br label %loop
loop:
%idx = phi i32 [ %start, %entry ], [ %idx.inc, %continue ], [ %idx.inc, %continue.1 ]
%postinc = phi i32 [ %postinc.start, %entry ], [ %postinc.inc, %continue ], [ %postinc.inc, %continue.1 ]
%postinc.inc = add nsw i32 %postinc, 1
%postinc.sext = sext i32 %postinc to i64
; CHECK: %postinc.sext = sext i32 %postinc to i64
; CHECK-NEXT: --> {(sext i32 (1 + %start) to i64),+,1}<nsw><%loop>
%break.early = icmp slt i32 %postinc, %low.limit
br i1 %break.early, label %continue.1, label %early.exit
continue.1:
%cond = load volatile i1, i1* %unknown
%idx.inc = add nsw i32 %idx, 1
br i1 %cond, label %loop, label %continue
continue:
%cmp = icmp slt i32 %idx.inc, %high.limit
br i1 %cmp, label %loop, label %exit
exit:
ret i64 0
early.exit:
ret i64 %postinc.sext
}
|