llvm-mirror/test/Transforms/InstCombine/sext.ll
Benjamin Kramer 7c0178b9ec InstCombine: Turn icmp + sext into bitwise/integer ops when the input has only one unknown bit.
int test1(unsigned x) { return (x&8) ? 0 : -1; }
int test3(unsigned x) { return (x&8) ? -1 : 0; }

before (x86_64):
_test1:
	andl	$8, %edi
	cmpl	$1, %edi
	sbbl	%eax, %eax
	ret
_test3:
	andl	$8, %edi
	cmpl	$1, %edi
	sbbl	%eax, %eax
	notl	%eax
	ret

after:
_test1:
	shrl	$3, %edi
	andl	$1, %edi
	leal	-1(%rdi), %eax
	ret
_test3:
	shll	$28, %edi
	movl	%edi, %eax
	sarl	$31, %eax
	ret

llvm-svn: 128732
2011-04-01 20:09:10 +00:00

187 lines
4.1 KiB
LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
declare i32 @llvm.ctpop.i32(i32)
declare i32 @llvm.ctlz.i32(i32)
declare i32 @llvm.cttz.i32(i32)
define i64 @test1(i32 %x) {
%t = call i32 @llvm.ctpop.i32(i32 %x)
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test1
; CHECK: zext i32 %t
}
define i64 @test2(i32 %x) {
%t = call i32 @llvm.ctlz.i32(i32 %x)
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test2
; CHECK: zext i32 %t
}
define i64 @test3(i32 %x) {
%t = call i32 @llvm.cttz.i32(i32 %x)
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test3
; CHECK: zext i32 %t
}
define i64 @test4(i32 %x) {
%t = udiv i32 %x, 3
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test4
; CHECK: zext i32 %t
}
define i64 @test5(i32 %x) {
%t = urem i32 %x, 30000
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test5
; CHECK: zext i32 %t
}
define i64 @test6(i32 %x) {
%u = lshr i32 %x, 3
%t = mul i32 %u, 3
%s = sext i32 %t to i64
ret i64 %s
; CHECK: @test6
; CHECK: zext i32 %t
}
define i64 @test7(i32 %x) {
%t = and i32 %x, 511
%u = sub i32 20000, %t
%s = sext i32 %u to i64
ret i64 %s
; CHECK: @test7
; CHECK: zext i32 %u to i64
}
define i32 @test8(i8 %a, i32 %f, i1 %p, i32* %z) {
%d = lshr i32 %f, 24
%e = select i1 %p, i32 %d, i32 0
%s = trunc i32 %e to i16
%n = sext i16 %s to i32
ret i32 %n
; CHECK: @test8
; CHECK: %d = lshr i32 %f, 24
; CHECK: %n = select i1 %p, i32 %d, i32 0
; CHECK: ret i32 %n
}
; rdar://6013816
define i16 @test9(i16 %t, i1 %cond) nounwind {
entry:
br i1 %cond, label %T, label %F
T:
%t2 = sext i16 %t to i32
br label %F
F:
%V = phi i32 [%t2, %T], [42, %entry]
%W = trunc i32 %V to i16
ret i16 %W
; CHECK: @test9
; CHECK: T:
; CHECK-NEXT: br label %F
; CHECK: F:
; CHECK-NEXT: phi i16
; CHECK-NEXT: ret i16
}
; PR2638
define i32 @test10(i32 %i) nounwind {
entry:
%tmp12 = trunc i32 %i to i8
%tmp16 = shl i8 %tmp12, 6
%a = ashr i8 %tmp16, 6
%b = sext i8 %a to i32
ret i32 %b
; CHECK: @test10
; CHECK: shl i32 %i, 30
; CHECK-NEXT: ashr exact i32
; CHECK-NEXT: ret i32
}
define void @test11(<2 x i16> %srcA, <2 x i16> %srcB, <2 x i16>* %dst) {
%cmp = icmp eq <2 x i16> %srcB, %srcA
%sext = sext <2 x i1> %cmp to <2 x i16>
%tmask = ashr <2 x i16> %sext, <i16 15, i16 15>
store <2 x i16> %tmask, <2 x i16>* %dst
ret void
; CHECK: @test11
; CHECK-NEXT: icmp eq
; CHECK-NEXT: sext <2 x i1>
; CHECK-NEXT: store <2 x i16>
; CHECK-NEXT: ret
}
define i64 @test12(i32 %x) nounwind {
%shr = lshr i32 %x, 1
%sub = sub nsw i32 0, %shr
%conv = sext i32 %sub to i64
ret i64 %conv
; CHECK: @test12
; CHECK: sext
; CHECK: ret
}
define i32 @test13(i32 %x) nounwind {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%ext = sext i1 %cmp to i32
ret i32 %ext
; CHECK: @test13
; CHECK-NEXT: %and = lshr i32 %x, 3
; CHECK-NEXT: %1 = and i32 %and, 1
; CHECK-NEXT: %sext = add i32 %1, -1
; CHECK-NEXT: ret i32 %sext
}
define i32 @test14(i16 %x) nounwind {
%and = and i16 %x, 16
%cmp = icmp ne i16 %and, 16
%ext = sext i1 %cmp to i32
ret i32 %ext
; CHECK: @test14
; CHECK-NEXT: %and = lshr i16 %x, 4
; CHECK-NEXT: %1 = and i16 %and, 1
; CHECK-NEXT: %sext = add i16 %1, -1
; CHECK-NEXT: %ext = sext i16 %sext to i32
; CHECK-NEXT: ret i32 %ext
}
define i32 @test15(i32 %x) nounwind {
%and = and i32 %x, 16
%cmp = icmp ne i32 %and, 0
%ext = sext i1 %cmp to i32
ret i32 %ext
; CHECK: @test15
; CHECK-NEXT: %1 = shl i32 %x, 27
; CHECK-NEXT: %sext = ashr i32 %1, 31
; CHECK-NEXT: ret i32 %sext
}
define i32 @test16(i16 %x) nounwind {
%and = and i16 %x, 8
%cmp = icmp eq i16 %and, 8
%ext = sext i1 %cmp to i32
ret i32 %ext
; CHECK: @test16
; CHECK-NEXT: %1 = shl i16 %x, 12
; CHECK-NEXT: %sext = ashr i16 %1, 15
; CHECK-NEXT: %ext = sext i16 %sext to i32
; CHECK-NEXT: ret i32 %ext
}