llvm/test/Analysis/ScalarEvolution/pr24757.ll
Sanjoy Das 8510b6c434 [ScalarEvolution] Fix PR24757.
Summary:
PR24757 was caused by some incorect math in
`ScalarEvolution::HowFarToZero` -- the smallest unsigned solution for X
in

  2^N * A = 2^N * X

is not necessarily A.

Reviewers: atrick, majnemer, meheff

Subscribers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D12721

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247242 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-10 05:27:38 +00:00

36 lines
982 B
LLVM

; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
; CHECK: Loop %bb1: backedge-taken count is (zext i7 (trunc i8 %a.promoted to i7) to i8)
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.10.0"
@a = global i8 -127, align 1
@b = common global i32 0, align 4
declare void @use(i32)
define i32 @main() {
bb:
%a.promoted = load i8, i8* @a
br label %bb1
bb1: ; preds = %bb1, %bb
%tmp = phi i8 [ %tmp2, %bb1 ], [ %a.promoted, %bb ]
%tmp2 = add i8 %tmp, -1
%tmp3 = sext i8 %tmp to i32
%tmp4 = xor i32 %tmp3, -1
%tmp5 = sext i8 %tmp2 to i32
%tmpf = sub nsw i32 %tmp4, %tmp5
%tmp6 = trunc i32 %tmpf to i8
%tmp7 = icmp eq i8 %tmp6, 0
br i1 %tmp7, label %bb8, label %bb1
bb8: ; preds = %bb1
store i8 %tmp2, i8* @a
store i32 %tmp4, i32* @b
%tmp9 = sext i8 %tmp2 to i32
call void @use(i32 %tmp9)
ret i32 0
}