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llvm-mirror/test/Instrumentation/MemorySanitizer/msan_llvm_is_constant.ll
Gui Andrade bb38b0a59d [MSAN] Pass Origin by parameter to __msan_warning functions
Summary:
Normally, the Origin is passed over TLS, which seems like it introduces unnecessary overhead. It's in the (extremely) cold path though, so the only overhead is in code size.

But with eager-checks, calls to __msan_warning functions are extremely common, so this becomes a useful optimization.

This can save ~5% code size.

Reviewers: eugenis, vitalybuka

Reviewed By: eugenis, vitalybuka

Subscribers: hiraditya, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D81700
2020-06-15 17:49:18 -07:00

25 lines
871 B
LLVM

; Make sure MSan doesn't insert shadow checks for @llvm.is.constant.* arguments.
; RUN: opt < %s -msan-kernel=1 -S -passes=msan 2>&1 | FileCheck \
; RUN: -check-prefixes=CHECK %s
; RUN: opt < %s -msan -msan-kernel=1 -S | FileCheck -check-prefixes=CHECK %s
; RUN: opt < %s -S -passes=msan 2>&1 | FileCheck -check-prefixes=CHECK %s
; RUN: opt < %s -msan -S | FileCheck -check-prefixes=CHECK %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind readnone uwtable
define dso_local i32 @bar(i32 %v) local_unnamed_addr sanitize_memory {
entry:
%0 = tail call i1 @llvm.is.constant.i32(i32 %v)
%1 = zext i1 %0 to i32
ret i32 %1
}
; CHECK-LABEL: bar
; CHECK-NOT: call void @__msan_warning_with_origin
; Function Attrs: nounwind readnone
declare i1 @llvm.is.constant.i32(i32)