caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
890c4bece26e005cd9fa5511fe0efa7307794de5
clang-p2996/llvm/test/Transforms/SimplifyCFG/speculate-derefable-load.ll
Nikita Popov 5a4c6f9799 [Loads] Check context instruction for context-sensitive derefability (#109277) 
If a dereferenceability fact is provided through `!dereferenceable` (or
similar), it may only hold on the given control flow path. When we use
`isSafeToSpeculativelyExecute()` to check multiple instructions, we
might make use of `!dereferenceable` information that does not hold at
the speculation target. This doesn't happen when speculating
instructions one by one, because `!dereferenceable` will be dropped
while speculating.

Fix this by checking whether the instruction with `!dereferenceable`
dominates the context instruction. If this is not the case, it means we
are speculating, and cannot guarantee that it holds at the speculation
target.

Fixes https://github.com/llvm/llvm-project/issues/108854.
2024-09-23 09:13:09 +02:00

193 lines
6.3 KiB
LLVM
Raw Blame History

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -S -passes=simplifycfg < %s | FileCheck %s
define i64 @align_deref_align(i1 %c, ptr %p) {
; CHECK-LABEL: define i64 @align_deref_align(
; CHECK-SAME: i1 [[C:%.*]], ptr [[P:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 8), "align"(ptr [[P]], i64 8) ]
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P]], align 8
; CHECK-NEXT: [[RES:%.*]] = select i1 [[C]], i64 [[V]], i64 0
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %p, i64 8), "align"(ptr %p, i64 8) ]
br i1 %c, label %if, label %exit
if:
%v = load i64, ptr %p, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if ], [ 0, %entry ]
ret i64 %res
}
define i64 @assume_deref_align2(i1 %c1, i32 %x, ptr %p) {
; CHECK-LABEL: define i64 @assume_deref_align2(
; CHECK-SAME: i1 [[C1:%.*]], i32 [[X:%.*]], ptr [[P:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 8), "align"(ptr [[P]], i64 8) ]
; CHECK-NEXT: [[C2:%.*]] = icmp ugt i32 [[X]], 10
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P]], align 8
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C2]], i64 [[V]], i64 1
; CHECK-NEXT: [[RES:%.*]] = select i1 [[C1]], i64 [[SPEC_SELECT]], i64 0
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %p, i64 8), "align"(ptr %p, i64 8) ]
br i1 %c1, label %if1, label %exit
if1:
%c2 = icmp ugt i32 %x, 10
br i1 %c2, label %if2, label %exit
if2:
%v = load i64, ptr %p, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if2 ], [ 1, %if1 ], [ 0, %entry ]
ret i64 %res
}
define i64 @assume_deref_align_not_dominating(i1 %c, ptr %p) {
; CHECK-LABEL: define i64 @assume_deref_align_not_dominating(
; CHECK-SAME: i1 [[C:%.*]], ptr [[P:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*]]:
; CHECK-NEXT: br i1 [[C]], label %[[IF:.*]], label %[[EXIT:.*]]
; CHECK: [[IF]]:
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P]], align 8
; CHECK-NEXT: br label %[[EXIT]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[V]], %[[IF]] ], [ 0, %[[ENTRY]] ]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "dereferenceable"(ptr [[P]], i64 8), "align"(ptr [[P]], i64 8) ]
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
br i1 %c, label %if, label %exit
if:
%v = load i64, ptr %p, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if ], [ 0, %entry ]
call void @llvm.assume(i1 true) [ "dereferenceable"(ptr %p, i64 8), "align"(ptr %p, i64 8) ]
ret i64 %res
}
define i64 @deref_no_hoist(i1 %c, ptr align 8 dereferenceable(8) %p1) {
; CHECK-LABEL: define i64 @deref_no_hoist(
; CHECK-SAME: i1 [[C:%.*]], ptr align 8 dereferenceable(8) [[P1:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*]]:
; CHECK-NEXT: br i1 [[C]], label %[[IF:.*]], label %[[EXIT:.*]]
; CHECK: [[IF]]:
; CHECK-NEXT: [[P2:%.*]] = load ptr, ptr [[P1]], align 8, !dereferenceable [[META0:![0-9]+]], !align [[META0]]
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P2]], align 8
; CHECK-NEXT: br label %[[EXIT]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[V]], %[[IF]] ], [ 0, %[[ENTRY]] ]
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
br i1 %c, label %if, label %exit
if:
%p2 = load ptr, ptr %p1, align 8, !dereferenceable !0, !align !0
%v = load i64, ptr %p2, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if ], [ 0, %entry ]
ret i64 %res
}
define i64 @deref_hoist(i1 %c, ptr align 8 dereferenceable(8) %p1) {
; CHECK-LABEL: define i64 @deref_hoist(
; CHECK-SAME: i1 [[C:%.*]], ptr align 8 dereferenceable(8) [[P1:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[P2:%.*]] = load ptr, ptr [[P1]], align 8, !dereferenceable [[META0]], !align [[META0]]
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P2]], align 8
; CHECK-NEXT: [[RES:%.*]] = select i1 [[C]], i64 [[V]], i64 0
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
%p2 = load ptr, ptr %p1, align 8, !dereferenceable !0, !align !0
br i1 %c, label %if, label %exit
if:
%v = load i64, ptr %p2, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if ], [ 0, %entry ]
ret i64 %res
}
define i64 @deref_no_hoist2(i1 %c1, i32 %x, ptr align 8 dereferenceable(8) %p1) {
; CHECK-LABEL: define i64 @deref_no_hoist2(
; CHECK-SAME: i1 [[C1:%.*]], i32 [[X:%.*]], ptr align 8 dereferenceable(8) [[P1:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*]]:
; CHECK-NEXT: br i1 [[C1]], label %[[IF1:.*]], label %[[EXIT:.*]]
; CHECK: [[IF1]]:
; CHECK-NEXT: [[C2:%.*]] = icmp ugt i32 [[X]], 10
; CHECK-NEXT: br i1 [[C2]], label %[[IF2:.*]], label %[[EXIT]]
; CHECK: [[IF2]]:
; CHECK-NEXT: [[P2:%.*]] = load ptr, ptr [[P1]], align 8, !dereferenceable [[META0]], !align [[META0]]
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P2]], align 8
; CHECK-NEXT: br label %[[EXIT]]
; CHECK: [[EXIT]]:
; CHECK-NEXT: [[RES:%.*]] = phi i64 [ [[V]], %[[IF2]] ], [ 1, %[[IF1]] ], [ 0, %[[ENTRY]] ]
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
br i1 %c1, label %if1, label %exit
if1:
%c2 = icmp ugt i32 %x, 10
br i1 %c2, label %if2, label %exit
if2:
%p2 = load ptr, ptr %p1, align 8, !dereferenceable !0, !align !0
%v = load i64, ptr %p2, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if2 ], [ 1, %if1 ], [ 0, %entry ]
ret i64 %res
}
define i64 @deref_hoist2(i1 %c1, i32 %x, ptr align 8 dereferenceable(8) %p1) {
; CHECK-LABEL: define i64 @deref_hoist2(
; CHECK-SAME: i1 [[C1:%.*]], i32 [[X:%.*]], ptr align 8 dereferenceable(8) [[P1:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[P2:%.*]] = load ptr, ptr [[P1]], align 8, !dereferenceable [[META0]], !align [[META0]]
; CHECK-NEXT: [[C2:%.*]] = icmp ugt i32 [[X]], 10
; CHECK-NEXT: [[V:%.*]] = load i64, ptr [[P2]], align 8
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[C2]], i64 [[V]], i64 1
; CHECK-NEXT: [[RES:%.*]] = select i1 [[C1]], i64 [[SPEC_SELECT]], i64 0
; CHECK-NEXT: ret i64 [[RES]]
;
entry:
%p2 = load ptr, ptr %p1, align 8, !dereferenceable !0, !align !0
br i1 %c1, label %if1, label %exit
if1:
%c2 = icmp ugt i32 %x, 10
br i1 %c2, label %if2, label %exit
if2:
%v = load i64, ptr %p2, align 8
br label %exit
exit:
%res = phi i64 [ %v, %if2 ], [ 1, %if1 ], [ 0, %entry ]
ret i64 %res
}
!0 = !{i64 8}
;.
; CHECK: [[META0]] = !{i64 8}
;.
Reference in New Issue View Git Blame Copy Permalink