llvm/test/Analysis/ScalarEvolution/min-max-exprs.ll
Sanjoy Das c05a5c2c86 [SCEV] Mark AddExprs as nsw or nuw if legal
Summary:
This uses `ScalarEvolution::getRange` and not potentially control
dependent `nsw` and `nuw` bits on the arithmetic instruction.

Reviewers: atrick, hfinkel, nlewycky

Subscribers: llvm-commits, sanjoy

Differential Revision: http://reviews.llvm.org/D13613

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251048 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-22 19:57:19 +00:00

54 lines
1.8 KiB
LLVM

; RUN: opt -scalar-evolution -analyze < %s | FileCheck %s
;
; This checks if the min and max expressions are properly recognized by
; ScalarEvolution even though they the ICmpInst and SelectInst have different
; types.
;
; #define max(a, b) (a > b ? a : b)
; #define min(a, b) (a < b ? a : b)
;
; void f(int *A, int N) {
; for (int i = 0; i < N; i++) {
; A[max(0, i - 3)] = A[min(N, i + 3)] * 2;
; }
; }
;
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
define void @f(i32* %A, i32 %N) {
bb:
br label %bb1
bb1: ; preds = %bb2, %bb
%i.0 = phi i32 [ 0, %bb ], [ %tmp23, %bb2 ]
%i.0.1 = sext i32 %i.0 to i64
%tmp = icmp slt i32 %i.0, %N
br i1 %tmp, label %bb2, label %bb24
bb2: ; preds = %bb1
%tmp3 = add nuw nsw i32 %i.0, 3
%tmp4 = icmp slt i32 %tmp3, %N
%tmp5 = sext i32 %tmp3 to i64
%tmp6 = sext i32 %N to i64
%tmp9 = select i1 %tmp4, i64 %tmp5, i64 %tmp6
; min(N, i+3)
; CHECK: select i1 %tmp4, i64 %tmp5, i64 %tmp6
; CHECK-NEXT: --> (-1 + (-1 * ((-1 + (-1 * (sext i32 {3,+,1}<nuw><%bb1> to i64))<nsw>)<nsw> smax (-1 + (-1 * (sext i32 %N to i64))<nsw>)<nsw>))<nsw>)<nsw>
%tmp11 = getelementptr inbounds i32, i32* %A, i64 %tmp9
%tmp12 = load i32, i32* %tmp11, align 4
%tmp13 = shl nsw i32 %tmp12, 1
%tmp14 = icmp sge i32 3, %i.0
%tmp17 = add nsw i64 %i.0.1, -3
%tmp19 = select i1 %tmp14, i64 0, i64 %tmp17
; max(0, i - 3)
; CHECK: select i1 %tmp14, i64 0, i64 %tmp17
; CHECK-NEXT: --> (-3 + (3 smax {0,+,1}<nuw><nsw><%bb1>))
%tmp21 = getelementptr inbounds i32, i32* %A, i64 %tmp19
store i32 %tmp13, i32* %tmp21, align 4
%tmp23 = add nuw nsw i32 %i.0, 1
br label %bb1
bb24: ; preds = %bb1
ret void
}