ee5585ed09
Improve and enable folding of conditional branches with tail calls. 1. Make it so that conditional tail calls can be emitted even when there are multiple predecessors. 2. Don't guard the transformation behind -Os. The rationale for guarding it was static-prediction can be affected by whether the branch is forward of backward. This is no longer true for almost any X86 cpus (anything newer than `SnB`) so is no longer a meaningful concern. Reviewed By: pengfei Differential Revision: https://reviews.llvm.org/D140931
30 lines
796 B
LLVM
30 lines
796 B
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
|
|
; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
|
|
|
|
declare dso_local void @bar()
|
|
|
|
define void @foo(ptr) {
|
|
; CHECK-LABEL: foo:
|
|
; CHECK: # %bb.0: # %start
|
|
; CHECK-NEXT: movl (%rdi), %eax
|
|
; CHECK-NEXT: andl $6, %eax
|
|
; CHECK-NEXT: cmpl $4, %eax
|
|
; CHECK-NEXT: jne bar # TAILCALL
|
|
; CHECK-NEXT: # %bb.1: # %bb1
|
|
; CHECK-NEXT: retq
|
|
start:
|
|
%1 = load i64, ptr %0, align 8, !range !0
|
|
%2 = and i64 %1, 6
|
|
%3 = icmp eq i64 %2, 4
|
|
br i1 %3, label %bb1, label %bb2.i
|
|
|
|
bb1: ; preds = %bb2.i, %start
|
|
ret void
|
|
|
|
bb2.i: ; preds = %start
|
|
tail call fastcc void @bar()
|
|
br label %bb1
|
|
}
|
|
|
|
!0 = !{i64 0, i64 6}
|