llvm-6502/test/CodeGen/X86/pmul.ll
Evan Cheng d498c8f2c8 Teach 2addr pass to be do more commuting. If both uses of a two-address instruction are killed, but the first operand has a use before and after the def, commute if the second operand does not suffer from the same issue.
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1028                                                                                                                                            
%reg1030<def> = ADD8rr %reg1028<kill>, %reg1029<kill>, %EFLAGS<imp-def,dead>                                                                                                         

In this case, it might not be possible to coalesce the second MOV8rr                                                                                                                 
instruction if the first one is coalesced. So it would be profitable to                                                                                                              
commute it:                                                                                                                                                                          
%reg1028<def> = EXTRACT_SUBREG %reg1027<kill>, 1                                                                                                                                     
%reg1029<def> = MOV8rr %reg1028                                                                                                                                                      
%reg1029<def> = SHR8ri %reg1029, 7, %EFLAGS<imp-def,dead>                                                                                                                            
insert => %reg1030<def> = MOV8rr %reg1029                                                                                                                                            
%reg1030<def> = ADD8rr %reg1029<kill>, %reg1028<kill>, %EFLAGS<imp-def,dead>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62954 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-25 03:53:59 +00:00

33 lines
989 B
LLVM

; RUN: llvm-as < %s | llc -march=x86 -mattr=sse41 -stack-alignment=16 > %t
; RUN: grep pmul %t | count 12
; RUN: grep mov %t | count 15
define <4 x i32> @a(<4 x i32> %i) nounwind {
%A = mul <4 x i32> %i, < i32 117, i32 117, i32 117, i32 117 >
ret <4 x i32> %A
}
define <2 x i64> @b(<2 x i64> %i) nounwind {
%A = mul <2 x i64> %i, < i64 117, i64 117 >
ret <2 x i64> %A
}
define <4 x i32> @c(<4 x i32> %i, <4 x i32> %j) nounwind {
%A = mul <4 x i32> %i, %j
ret <4 x i32> %A
}
define <2 x i64> @d(<2 x i64> %i, <2 x i64> %j) nounwind {
%A = mul <2 x i64> %i, %j
ret <2 x i64> %A
}
; Use a call to force spills.
declare void @foo()
define <4 x i32> @e(<4 x i32> %i, <4 x i32> %j) nounwind {
call void @foo()
%A = mul <4 x i32> %i, %j
ret <4 x i32> %A
}
define <2 x i64> @f(<2 x i64> %i, <2 x i64> %j) nounwind {
call void @foo()
%A = mul <2 x i64> %i, %j
ret <2 x i64> %A
}