File: branch-target-layout.c

package info (click to toggle)
llvm-toolchain-11 1%3A11.0.1-2~deb10u1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 995,836 kB
  • sloc: cpp: 4,767,656; ansic: 760,916; asm: 477,436; python: 170,940; objc: 69,804; lisp: 29,914; sh: 23,855; f90: 18,173; pascal: 7,551; perl: 7,471; ml: 5,603; awk: 3,489; makefile: 2,573; xml: 915; cs: 573; fortran: 503; javascript: 452
file content (40 lines) | stat: -rw-r--r-- 873 bytes parent folder | download | duplicates (24) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
 
// RUN: %clang_cc1 %s -O3 -emit-llvm -o - | FileCheck %s
//
// PR13214
// No assumption may be made about the order that a frontend emits branch
// targets (basic blocks). However, the backend's basic block layout makes an
// attempt to preserve source order of control flow, and any bias toward source
// order must start with the frontend.
//
// Note that the frontend inverts branches to simplify the condition, so the
// order of a branch instruction's labels cannot be used as a source order bias.

void calla();
void callb();
void callc();

// CHECK: @test1
// CHECK: @calla
// CHECK: @callb
// CHECK: @callc
// CHECK: ret void
void test1(int a) {
  if (a)
    calla();
  else
    callb();
  callc();
}

// CHECK: @test2
// CHECK: @callb
// CHECK: @calla
// CHECK: @callc
// CHECK: ret void
void test2(int a) {
  if (!a)
    callb();
  else
    calla();
  callc();
}