llvm/test/Transforms/InstCombine/2011-05-28-swapmulsub.ll
Matt Arsenault 9e6badc7e1 Reapply "InstCombine: Reduce trunc (shl x, K) width."
This reapplies r272987 with a fix for infinitely looping
when the truncated value is another shift of a constant.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281379 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-13 19:43:57 +00:00

60 lines
1.6 KiB
LLVM

; ModuleID = 'test1.c'
; RUN: opt -S -instcombine < %s | FileCheck %s
target triple = "x86_64-apple-macosx10.6.6"
define zeroext i16 @foo1(i32 %on_off) nounwind uwtable ssp {
entry:
%on_off.addr = alloca i32, align 4
%a = alloca i32, align 4
store i32 %on_off, i32* %on_off.addr, align 4
%tmp = load i32, i32* %on_off.addr, align 4
%sub = sub i32 1, %tmp
; CHECK-NOT: mul i32
%mul = mul i32 %sub, -2
; CHECK: shl
; CHECK-NEXT: add
store i32 %mul, i32* %a, align 4
%tmp1 = load i32, i32* %a, align 4
%conv = trunc i32 %tmp1 to i16
ret i16 %conv
}
define zeroext i16 @foo2(i32 %on_off, i32 %q) nounwind uwtable ssp {
entry:
%on_off.addr = alloca i32, align 4
%q.addr = alloca i32, align 4
%a = alloca i32, align 4
store i32 %on_off, i32* %on_off.addr, align 4
store i32 %q, i32* %q.addr, align 4
%tmp = load i32, i32* %q.addr, align 4
%tmp1 = load i32, i32* %on_off.addr, align 4
%sub = sub i32 %tmp, %tmp1
; CHECK-NOT: mul i32
%mul = mul i32 %sub, -4
; CHECK: sub i32
; CHECK-NEXT: trunc i32
; CHECK-NEXT: %conv = shl i16 %{{.*}}, 2
; CHECK-NEXT: ret i16 %conv
store i32 %mul, i32* %a, align 4
%tmp2 = load i32, i32* %a, align 4
%conv = trunc i32 %tmp2 to i16
ret i16 %conv
}
define zeroext i16 @foo3(i32 %on_off) nounwind uwtable ssp {
entry:
%on_off.addr = alloca i32, align 4
%a = alloca i32, align 4
store i32 %on_off, i32* %on_off.addr, align 4
%tmp = load i32, i32* %on_off.addr, align 4
%sub = sub i32 7, %tmp
; CHECK-NOT: mul i32
%mul = mul i32 %sub, -4
; CHECK: shl
; CHECK-NEXT: add
store i32 %mul, i32* %a, align 4
%tmp1 = load i32, i32* %a, align 4
%conv = trunc i32 %tmp1 to i16
ret i16 %conv
}