llvm/test/CodeGen/X86/peep-test-4.ll
Benjamin Kramer 202be06318 X86: If we have an instruction that sets a flag and a zero test on the input of that instruction try to eliminate the test.
For example
	tzcntl	%edi, %ebx
	testl %edi, %edi
	je	.label

can be rewritten into
	tzcntl	%edi, %ebx
	jb 	.label

A minor complication is that tzcnt sets CF instead of ZF when the input
is zero, we have to rewrite users of the flags from ZF to CF. Currently
we recognize patterns using lzcnt, tzcnt and popcnt.

Differential Revision: http://reviews.llvm.org/D3454

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208788 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-14 16:14:45 +00:00

266 lines
5.2 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-pc-linux -mattr=+bmi,+bmi2,+popcnt,+lzcnt | FileCheck %s
declare void @foo(i32)
declare void @foo32(i32)
declare void @foo64(i64)
; CHECK-LABEL: neg:
; CHECK: negl %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @neg(i32 %x) nounwind {
%sub = sub i32 0, %x
%cmp = icmp eq i32 %sub, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %sub)
br label %return
return:
ret void
}
; CHECK-LABEL: sar:
; CHECK: sarl %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @sar(i32 %x) nounwind {
%ashr = ashr i32 %x, 1
%cmp = icmp eq i32 %ashr, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %ashr)
br label %return
return:
ret void
}
; CHECK-LABEL: shr:
; CHECK: shrl %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @shr(i32 %x) nounwind {
%ashr = lshr i32 %x, 1
%cmp = icmp eq i32 %ashr, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %ashr)
br label %return
return:
ret void
}
; CHECK-LABEL: shri:
; CHECK: shrl $3, %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @shri(i32 %x) nounwind {
%ashr = lshr i32 %x, 3
%cmp = icmp eq i32 %ashr, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %ashr)
br label %return
return:
ret void
}
; CHECK-LABEL: shl:
; CHECK: addl %edi, %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @shl(i32 %x) nounwind {
%shl = shl i32 %x, 1
%cmp = icmp eq i32 %shl, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %shl)
br label %return
return:
ret void
}
; CHECK-LABEL: shli:
; CHECK: shll $4, %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @shli(i32 %x) nounwind {
%shl = shl i32 %x, 4
%cmp = icmp eq i32 %shl, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %shl)
br label %return
return:
ret void
}
; CHECK-LABEL: adc:
; CHECK: movabsq $-9223372036854775808, %rax
; CHECK-NEXT: addq %rdi, %rax
; CHECK-NEXT: adcq $0, %rsi
; CHECK-NEXT: sete %al
; CHECK: ret
define zeroext i1 @adc(i128 %x) nounwind {
%add = add i128 %x, 9223372036854775808
%cmp = icmp ult i128 %add, 18446744073709551616
ret i1 %cmp
}
; CHECK-LABEL: sbb:
; CHECK: cmpq %rdx, %rdi
; CHECK-NEXT: sbbq %rcx, %rsi
; CHECK-NEXT: setns %al
; CHECK: ret
define zeroext i1 @sbb(i128 %x, i128 %y) nounwind {
%sub = sub i128 %x, %y
%cmp = icmp sge i128 %sub, 0
ret i1 %cmp
}
; CHECK-LABEL: andn:
; CHECK: andnl %esi, %edi, %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
define void @andn(i32 %x, i32 %y) nounwind {
%not = xor i32 %x, -1
%andn = and i32 %y, %not
%cmp = icmp eq i32 %andn, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %andn)
br label %return
return:
ret void
}
; CHECK-LABEL: bextr:
; CHECK: bextrl %esi, %edi, %edi
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
declare i32 @llvm.x86.bmi.bextr.32(i32, i32) nounwind readnone
define void @bextr(i32 %x, i32 %y) nounwind {
%bextr = tail call i32 @llvm.x86.bmi.bextr.32(i32 %x, i32 %y)
%cmp = icmp eq i32 %bextr, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %bextr)
br label %return
return:
ret void
}
; CHECK-LABEL: popcnt:
; CHECK: popcntl
; CHECK-NEXT: je
; CHECK: jmp foo
; CHECK: ret
declare i32 @llvm.ctpop.i32(i32) nounwind readnone
define void @popcnt(i32 %x) nounwind {
%popcnt = tail call i32 @llvm.ctpop.i32(i32 %x)
%cmp = icmp eq i32 %popcnt, 0
br i1 %cmp, label %return, label %bb
;
bb:
tail call void @foo(i32 %popcnt)
br label %return
;
return:
ret void
}
; CHECK-LABEL: testCTZ
; CHECK: tzcntq
; CHECK-NOT: test
; CHECK: cmovaeq
declare i64 @llvm.cttz.i64(i64, i1)
define i64 @testCTZ(i64 %v) nounwind {
%cnt = tail call i64 @llvm.cttz.i64(i64 %v, i1 true)
%tobool = icmp eq i64 %v, 0
%cond = select i1 %tobool, i64 255, i64 %cnt
ret i64 %cond
}
; CHECK-LABEL: testCTZ2
; CHECK: tzcntl
; CHECK-NEXT: jb
; CHECK: jmp foo
declare i32 @llvm.cttz.i32(i32, i1)
define void @testCTZ2(i32 %v) nounwind {
%cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
%cmp = icmp eq i32 %v, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %cnt)
br label %return
return:
tail call void @foo32(i32 %cnt)
ret void
}
; CHECK-LABEL: testCTZ3
; CHECK: tzcntl
; CHECK-NEXT: jae
; CHECK: jmp foo
define void @testCTZ3(i32 %v) nounwind {
%cnt = tail call i32 @llvm.cttz.i32(i32 %v, i1 true)
%cmp = icmp ne i32 %v, 0
br i1 %cmp, label %return, label %bb
bb:
tail call void @foo(i32 %cnt)
br label %return
return:
tail call void @foo32(i32 %cnt)
ret void
}
; CHECK-LABEL: testCLZ
; CHECK: lzcntq
; CHECK-NOT: test
; CHECK: cmovaeq
declare i64 @llvm.ctlz.i64(i64, i1)
define i64 @testCLZ(i64 %v) nounwind {
%cnt = tail call i64 @llvm.ctlz.i64(i64 %v, i1 true)
%tobool = icmp ne i64 %v, 0
%cond = select i1 %tobool, i64 %cnt, i64 255
ret i64 %cond
}
; CHECK-LABEL: testPOPCNT
; CHECK: popcntq
; CHECK-NOT: test
; CHECK: cmovneq
declare i64 @llvm.ctpop.i64(i64)
define i64 @testPOPCNT(i64 %v) nounwind {
%cnt = tail call i64 @llvm.ctpop.i64(i64 %v)
%tobool = icmp ne i64 %v, 0
%cond = select i1 %tobool, i64 %cnt, i64 255
ret i64 %cond
}