// Solve the general equation.
const SCEV *E = SolveLinEquationWithOverflow(StepC->getAPInt(),
getNegativeSCEV(Start), *this);
- const SCEV *M = E == getCouldNotCompute()
- ? E
- : getConstant(getUnsignedRangeMax(E));
+
+ const SCEV *M = E;
+ if (E != getCouldNotCompute()) {
+ APInt MaxWithGuards = getUnsignedRangeMax(applyLoopGuards(E, L));
+ M = getConstant(APIntOps::umin(MaxWithGuards, getUnsignedRangeMax(E)));
+ }
return ExitLimit(E, M, false, Predicates);
}
ret i32 0
}
-; Test case from PR52464.
-define i32 @rewrite_zext_icmp_ne(i32 %N) {
-; CHECK-LABEL: Determining loop execution counts for: @rewrite_zext_icmp_ne
-; CHECK-NEXT: Loop %loop: backedge-taken count is ((-4 + (4 * ((4 + (zext i32 (-1 + (zext i2 (trunc i32 %N to i2) to i32))<nsw> to i64))<nuw><nsw> /u 4))<nuw><nsw>)<nsw> /u 4)
-; CHECK-NEXT: Loop %loop: max backedge-taken count is 1073741823
-; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is ((-4 + (4 * ((4 + (zext i32 (-1 + (zext i2 (trunc i32 %N to i2) to i32))<nsw> to i64))<nuw><nsw> /u 4))<nuw><nsw>)<nsw> /u 4)
+; Test case from PR52464. applyLoopGuards needs to apply information about %and
+; to %ext, which requires rewriting the zext.
+define i32 @rewrite_zext_with_info_from_icmp_ne(i32 %N) {
+; CHECK-LABEL: Determining loop execution counts for: @rewrite_zext_with_info_from_icmp_ne
+; CHECK-NEXT: Loop %loop: backedge-taken count is 0
+; CHECK-NEXT: Loop %loop: max backedge-taken count is 0
+; CHECK-NEXT: Loop %loop: Predicated backedge-taken count is 0
; CHECK-NEXT: Predicates:
; CHECK-EMPTY:
; CHECK-NEXT: Loop %loop: Trip multiple is 1
ret i32 0
}
-; Similar to @rewrite_zext_icmp_ne, but the loop is not guarded by %and != 0,
+; Similar to @rewrite_zext_with_info_from_icmp_ne, but the loop is not guarded by %and != 0,
; hence the subsequent subtraction may yield a negative number.
define i32 @rewrite_zext_no_icmp_ne(i32 %N) {
; CHECK-LABEL: Determining loop execution counts for: @rewrite_zext_no_icmp_ne