File: branch-target-layout.c

package info (click to toggle)
llvm-toolchain-16 1%3A16.0.6-15~deb11u2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 1,634,820 kB
  • sloc: cpp: 6,179,261; ansic: 1,216,205; asm: 741,319; python: 196,614; objc: 75,325; f90: 49,640; lisp: 32,396; pascal: 12,286; sh: 9,394; perl: 7,442; ml: 5,494; awk: 3,523; makefile: 2,723; javascript: 1,206; xml: 886; fortran: 581; cs: 573
file content (40 lines) | stat: -rw-r--r-- 885 bytes parent folder | download | duplicates (13) 
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);
void callb(void);
void callc(void);

// 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();
}