mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-08 18:30:04 +00:00
ff56d1a201
On cores for which we know the misprediction penalty, and we have the isel instruction, we can profitably perform early if conversion. This enables us to replace some small branch sequences with selects and avoid the potential stalls from mispredicting the branches. Enabling this feature required implementing canInsertSelect and insertSelect in PPCInstrInfo; isel code in PPCISelLowering was refactored to use these functions as well. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178926 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
1.2 KiB
LLVM
35 lines
1.2 KiB
LLVM
; RUN: llc < %s -mtriple=powerpc64-unknown-linux-gnu -mcpu=pwr7 -verify-machineinstrs | 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-f128:128:128-v128:128:128-n32:64"
|
|
target triple = "powerpc64-unknown-linux-gnu"
|
|
|
|
define i32 @test(i32 %a, i32 %b, i32 %c, i32 %d) {
|
|
entry:
|
|
%sext82 = shl i32 %d, 16
|
|
%conv29 = ashr exact i32 %sext82, 16
|
|
%cmp = icmp slt i32 %sext82, 0
|
|
br i1 %cmp, label %cond.true, label %cond.false
|
|
|
|
cond.true: ; preds = %sw.epilog
|
|
%and33 = and i32 %conv29, 32767
|
|
%sub34 = sub nsw i32 %a, %and33
|
|
br label %cond.end
|
|
|
|
cond.false: ; preds = %sw.epilog
|
|
%add37 = add nsw i32 %conv29, %a
|
|
br label %cond.end
|
|
|
|
; CHECK: @test
|
|
; CHECK: add [[REG:[0-9]+]],
|
|
; CHECK: subf [[REG2:[0-9]+]],
|
|
; CHECK: isel {{[0-9]+}}, [[REG]], [[REG2]],
|
|
|
|
cond.end: ; preds = %cond.false, %cond.true
|
|
%cond = phi i32 [ %sub34, %cond.true ], [ %add37, %cond.false ]
|
|
%sext83 = shl i32 %cond, 16
|
|
%conv39 = ashr exact i32 %sext83, 16
|
|
%add41 = sub i32 %b, %a
|
|
%sub43 = add i32 %add41, %conv39
|
|
ret i32 %sub43
|
|
}
|
|
|