llvm/test/CodeGen/X86/2009-04-25-CoalescerBug.ll
Wei Mi 31333a7c12 Recommit 'Remove the restriction that MachineSinking is now stopped by
"insert_subreg, subreg_to_reg, and reg_sequence" instructions' after
adjusting some unittest checks.

This is to solve PR28852. The restriction was added at 2010 to make better register
coalescing. We assumed that it was not necessary any more. Testing results on x86
supported the assumption.

We will look closely to any performance impact it will bring and will be prepared
to help analyzing performance problem found on other architectures.

Differential Revision: https://reviews.llvm.org/D23210


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278466 91177308-0d34-0410-b5e6-96231b3b80d8
2016-08-12 03:33:22 +00:00

20 lines
627 B
LLVM

; RUN: llc < %s -march=x86-64 | grep mov | count 1
; rdar://6806252
define i64 @test(i32* %tmp13) nounwind {
entry:
br label %while.cond
while.cond: ; preds = %while.cond, %entry
%tmp15 = load i32, i32* %tmp13 ; <i32> [#uses=2]
%bf.lo = lshr i32 %tmp15, 1 ; <i32> [#uses=1]
%bf.lo.cleared = and i32 %bf.lo, 2147483647 ; <i32> [#uses=1]
%conv = zext i32 %bf.lo.cleared to i64 ; <i64> [#uses=1]
%bf.lo.cleared25 = and i32 %tmp15, 1 ; <i32> [#uses=1]
%tobool = icmp ne i32 %bf.lo.cleared25, 0 ; <i1> [#uses=1]
br i1 %tobool, label %while.cond, label %while.end
while.end: ; preds = %while.cond
ret i64 %conv
}