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llvm-mirror/test/Analysis/ValueTracking/known-nonnull-at.ll
Sanjay Patel 8e7e7e2058 [ValueTracking] use nonnull argument attribute to eliminate null checks
Enhancing value tracking's analysis of null-ness was suggested in D27855, so here's a first attempt at that.

This is part of solving:
https://llvm.org/bugs/show_bug.cgi?id=28430

Differential Revision: https://reviews.llvm.org/D28204

llvm-svn: 294897
2017-02-12 15:35:34 +00:00

101 lines
2.5 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -instsimplify < %s | FileCheck %s
declare void @bar(i8* %a, i8* nonnull %b)
; 'y' must be nonnull.
define i1 @caller1(i8* %x, i8* %y) {
; CHECK-LABEL: @caller1(
; CHECK-NEXT: call void @bar(i8* %x, i8* %y)
; CHECK-NEXT: ret i1 false
;
call void @bar(i8* %x, i8* %y)
%null_check = icmp eq i8* %y, null
ret i1 %null_check
}
; Don't know anything about 'y'.
define i1 @caller2(i8* %x, i8* %y) {
; CHECK-LABEL: @caller2(
; CHECK-NEXT: call void @bar(i8* %y, i8* %x)
; CHECK-NEXT: [[NULL_CHECK:%.*]] = icmp eq i8* %y, null
; CHECK-NEXT: ret i1 [[NULL_CHECK]]
;
call void @bar(i8* %y, i8* %x)
%null_check = icmp eq i8* %y, null
ret i1 %null_check
}
; 'y' must be nonnull.
define i1 @caller3(i8* %x, i8* %y) {
; CHECK-LABEL: @caller3(
; CHECK-NEXT: call void @bar(i8* %x, i8* %y)
; CHECK-NEXT: ret i1 true
;
call void @bar(i8* %x, i8* %y)
%null_check = icmp ne i8* %y, null
ret i1 %null_check
}
; FIXME: The call is guaranteed to execute, so 'y' must be nonnull throughout.
define i1 @caller4(i8* %x, i8* %y) {
; CHECK-LABEL: @caller4(
; CHECK-NEXT: [[NULL_CHECK:%.*]] = icmp ne i8* %y, null
; CHECK-NEXT: call void @bar(i8* %x, i8* %y)
; CHECK-NEXT: ret i1 [[NULL_CHECK]]
;
%null_check = icmp ne i8* %y, null
call void @bar(i8* %x, i8* %y)
ret i1 %null_check
}
; The call to bar() does not dominate the null check, so no change.
define i1 @caller5(i8* %x, i8* %y) {
; CHECK-LABEL: @caller5(
; CHECK-NEXT: [[NULL_CHECK:%.*]] = icmp eq i8* %y, null
; CHECK-NEXT: br i1 [[NULL_CHECK]], label %t, label %f
; CHECK: t:
; CHECK-NEXT: ret i1 [[NULL_CHECK]]
; CHECK: f:
; CHECK-NEXT: call void @bar(i8* %x, i8* %y)
; CHECK-NEXT: ret i1 [[NULL_CHECK]]
;
%null_check = icmp eq i8* %y, null
br i1 %null_check, label %t, label %f
t:
ret i1 %null_check
f:
call void @bar(i8* %x, i8* %y)
ret i1 %null_check
}
; Make sure that an invoke works similarly to a call.
declare i32 @esfp(...)
define i1 @caller6(i8* %x, i8* %y) personality i8* bitcast (i32 (...)* @esfp to i8*){
; CHECK-LABEL: @caller6(
; CHECK-NEXT: invoke void @bar(i8* %x, i8* nonnull %y)
; CHECK-NEXT: to label %cont unwind label %exc
; CHECK: cont:
; CHECK-NEXT: ret i1 false
;
invoke void @bar(i8* %x, i8* nonnull %y)
to label %cont unwind label %exc
cont:
%null_check = icmp eq i8* %y, null
ret i1 %null_check
exc:
%lp = landingpad { i8*, i32 }
filter [0 x i8*] zeroinitializer
unreachable
}