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clang-p2996/llvm/test/Transforms/InstCombine/malloc-free.ll
Shoaib Meenai 6404f4b5af [InstCombine] Remove attributes after hoisting free above null check 
If the parameter had been annotated as nonnull because of the null
check, we want to remove the attribute, since it may no longer apply and
could result in miscompiles if left. Similarly, we also want to remove
undef-implying attributes, since they may not apply anymore either.

Fixes PR52110.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D111515
2021-10-13 15:34:56 -07:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; PR1201
define i32 @main(i32 %argc, i8** %argv) {
; CHECK-LABEL: @main(
; CHECK-NEXT: ret i32 0
;
%c_19 = alloca i8*
%malloc_206 = tail call i8* @malloc(i32 mul (i32 ptrtoint (i8* getelementptr (i8, i8* null, i32 1) to i32), i32 10))
store i8* %malloc_206, i8** %c_19
%tmp_207 = load i8*, i8** %c_19
tail call void @free(i8* %tmp_207)
ret i32 0
}
define i32 @dead_aligned_alloc(i32 %size, i32 %alignment, i8 %value) {
; CHECK-LABEL: @dead_aligned_alloc(
; CHECK-NEXT: ret i32 0
;
%aligned_allocation = tail call i8* @aligned_alloc(i32 %alignment, i32 %size)
store i8 %value, i8* %aligned_allocation
tail call void @free(i8* %aligned_allocation)
ret i32 0
}
declare noalias i8* @calloc(i32, i32) nounwind
declare noalias i8* @malloc(i32)
declare noalias i8* @aligned_alloc(i32, i32)
declare void @free(i8*)
define i1 @foo() {
; CHECK-LABEL: @foo(
; CHECK-NEXT: ret i1 false
;
%m = call i8* @malloc(i32 1)
%z = icmp eq i8* %m, null
call void @free(i8* %m)
ret i1 %z
}
declare void @llvm.lifetime.start.p0i8(i64, i8*)
declare void @llvm.lifetime.end.p0i8(i64, i8*)
declare i64 @llvm.objectsize.i64(i8*, i1)
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i1) nounwind
declare void @llvm.memmove.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i1) nounwind
declare void @llvm.memset.p0i8.i32(i8*, i8, i32, i1) nounwind
define void @test3(i8* %src) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: ret void
;
%a = call noalias i8* @malloc(i32 10)
call void @llvm.lifetime.start.p0i8(i64 10, i8* %a)
call void @llvm.lifetime.end.p0i8(i64 10, i8* %a)
%size = call i64 @llvm.objectsize.i64(i8* %a, i1 true)
store i8 42, i8* %a
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a, i8* %src, i32 32, i1 false)
call void @llvm.memmove.p0i8.p0i8.i32(i8* %a, i8* %src, i32 32, i1 false)
call void @llvm.memset.p0i8.i32(i8* %a, i8 5, i32 32, i1 false)
%alloc2 = call noalias i8* @calloc(i32 5, i32 7) nounwind
%z = icmp ne i8* %alloc2, null
ret void
}
;; This used to crash.
define void @test4() {
; CHECK-LABEL: @test4(
; CHECK-NEXT: ret void
;
%A = call i8* @malloc(i32 16000)
%B = bitcast i8* %A to double*
%C = bitcast double* %B to i8*
call void @free(i8* %C)
ret void
}
define void @test5(i8* %ptr, i8** %esc) {
; CHECK-LABEL: @test5(
; CHECK-NEXT: [[A:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[B:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[C:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[D:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[E:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[F:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: [[G:%.*]] = call dereferenceable_or_null(700) i8* @malloc(i32 700)
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* noundef nonnull align 1 dereferenceable(32) [[PTR:%.*]], i8* noundef nonnull align 1 dereferenceable(32) [[A]], i32 32, i1 false)
; CHECK-NEXT: call void @llvm.memmove.p0i8.p0i8.i32(i8* noundef nonnull align 1 dereferenceable(32) [[PTR]], i8* noundef nonnull align 1 dereferenceable(32) [[B]], i32 32, i1 false)
; CHECK-NEXT: store i8* [[C]], i8** [[ESC:%.*]], align 8
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* [[D]], i8* [[PTR]], i32 32, i1 true)
; CHECK-NEXT: call void @llvm.memmove.p0i8.p0i8.i32(i8* [[E]], i8* [[PTR]], i32 32, i1 true)
; CHECK-NEXT: call void @llvm.memset.p0i8.i32(i8* [[F]], i8 5, i32 32, i1 true)
; CHECK-NEXT: store volatile i8 4, i8* [[G]], align 1
; CHECK-NEXT: ret void
;
%a = call i8* @malloc(i32 700)
%b = call i8* @malloc(i32 700)
%c = call i8* @malloc(i32 700)
%d = call i8* @malloc(i32 700)
%e = call i8* @malloc(i32 700)
%f = call i8* @malloc(i32 700)
%g = call i8* @malloc(i32 700)
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %ptr, i8* %a, i32 32, i1 false)
call void @llvm.memmove.p0i8.p0i8.i32(i8* %ptr, i8* %b, i32 32, i1 false)
store i8* %c, i8** %esc
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %d, i8* %ptr, i32 32, i1 true)
call void @llvm.memmove.p0i8.p0i8.i32(i8* %e, i8* %ptr, i32 32, i1 true)
call void @llvm.memset.p0i8.i32(i8* %f, i8 5, i32 32, i1 true)
store volatile i8 4, i8* %g
ret void
}
;; When a basic block contains only a call to free and this block is accessed
;; through a test of the argument of free against null, move the call in the
;; predecessor block.
;; Using simplifycfg will remove the empty basic block and the branch operation
;; Then, performing a dead elimination will remove the comparison.
;; This is what happens with -O1 and upper.
define void @test6(i8* %foo) minsize {
; CHECK-LABEL: @test6(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i8* [[FOO:%.*]], null
; CHECK-NEXT: tail call void @free(i8* [[FOO]])
; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: ret void
;
;; Call to free moved
;; Block is now empty and may be simplified by simplifycfg
entry:
%tobool = icmp eq i8* %foo, null
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @free(i8* %foo)
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
;; Check that the optimization that moves a call to free in its predecessor
;; block (see test6) also happens when noop casts are involved.
define void @test12(i32* %foo) minsize {
; CHECK-LABEL: @test12(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i32* [[FOO:%.*]], null
; CHECK-NEXT: [[BITCAST:%.*]] = bitcast i32* [[FOO]] to i8*
; CHECK-NEXT: tail call void @free(i8* [[BITCAST]])
; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: ret void
;
;; Everything before the call to free should have been moved as well.
;; Call to free moved
;; Block is now empty and may be simplified by simplifycfg
entry:
%tobool = icmp eq i32* %foo, null
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
%bitcast = bitcast i32* %foo to i8*
tail call void @free(i8* %bitcast)
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
;; Test that nonnull-implying attributes on the parameter are adjusted when the
;; call is moved, since they may no longer be valid and result in miscompiles if
;; kept unchanged.
define void @test_nonnull_free_move(i8* %foo) minsize {
; CHECK-LABEL: @test_nonnull_free_move(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i8* [[FOO:%.*]], null
; CHECK-NEXT: tail call void @free(i8* [[FOO]])
; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: ret void
;
entry:
%tobool = icmp eq i8* %foo, null
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @free(i8* nonnull %foo)
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
define void @test_dereferenceable_free_move(i8* %foo) minsize {
; CHECK-LABEL: @test_dereferenceable_free_move(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i8* [[FOO:%.*]], null
; CHECK-NEXT: tail call void @free(i8* dereferenceable_or_null(4) [[FOO]])
; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: ret void
;
entry:
%tobool = icmp eq i8* %foo, null
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @free(i8* dereferenceable(4) %foo)
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
define void @test_nonnull_dereferenceable_free_move(i8* %foo) minsize {
; CHECK-LABEL: @test_nonnull_dereferenceable_free_move(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TOBOOL:%.*]] = icmp eq i8* [[FOO:%.*]], null
; CHECK-NEXT: tail call void @free(i8* dereferenceable_or_null(16) [[FOO]])
; CHECK-NEXT: br i1 [[TOBOOL]], label [[IF_END:%.*]], label [[IF_THEN:%.*]]
; CHECK: if.then:
; CHECK-NEXT: br label [[IF_END]]
; CHECK: if.end:
; CHECK-NEXT: ret void
;
entry:
%tobool = icmp eq i8* %foo, null
br i1 %tobool, label %if.end, label %if.then
if.then: ; preds = %entry
tail call void @free(i8* nonnull dereferenceable(16) %foo)
br label %if.end
if.end: ; preds = %entry, %if.then
ret void
}
; The next four tests cover the semantics of the nofree attributes. These
; are thought to be legal transforms, but an implementation thereof has
; been reverted once due to difficult to isolate fallout.
; TODO: Freeing a no-free pointer -> %foo must be null
define void @test13(i8* nofree %foo) {
; CHECK-LABEL: @test13(
; CHECK-NEXT: call void @free(i8* [[FOO:%.*]])
; CHECK-NEXT: ret void
;
call void @free(i8* %foo)
ret void
}
; TODO: Freeing a no-free pointer -> %foo must be null
define void @test14(i8* %foo) nofree {
; CHECK-LABEL: @test14(
; CHECK-NEXT: call void @free(i8* [[FOO:%.*]])
; CHECK-NEXT: ret void
;
call void @free(i8* %foo)
ret void
}
; TODO: free call marked no-free -> %foo must be null
define void @test15(i8* %foo) {
; CHECK-LABEL: @test15(
; CHECK-NEXT: call void @free(i8* [[FOO:%.*]]) #[[ATTR5:[0-9]+]]
; CHECK-NEXT: ret void
;
call void @free(i8* %foo) nofree
ret void
}
; TODO: freeing a nonnull nofree pointer -> full UB
define void @test16(i8* nonnull nofree %foo) {
; CHECK-LABEL: @test16(
; CHECK-NEXT: call void @free(i8* [[FOO:%.*]])
; CHECK-NEXT: ret void
;
call void @free(i8* %foo)
ret void
}
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