Legalizer optimize a pair of div / mod to a call to divrem libcall if they are

not legal. However, it should use a div instruction + mul + sub if divide is
legal. The rem legalization code was missing a check and incorrectly uses a
divrem libcall even when div is legal.

rdar://12481395


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165778 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2012-10-12 01:15:47 +00:00
parent 5665a3dbc9
commit d36696c4e0
2 changed files with 36 additions and 12 deletions

View File

@ -3153,6 +3153,8 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
Tmp3 = Node->getOperand(1);
if (TLI.isOperationLegalOrCustom(DivRemOpc, VT) ||
(isDivRemLibcallAvailable(Node, isSigned, TLI) &&
// If div is legal, it's better to do the normal expansion
!TLI.isOperationLegalOrCustom(DivOpc, Node->getValueType(0)) &&
useDivRem(Node, isSigned, false))) {
Tmp1 = DAG.getNode(DivRemOpc, dl, VTs, Tmp2, Tmp3).getValue(1);
} else if (TLI.isOperationLegalOrCustom(DivOpc, VT)) {

View File

@ -1,10 +1,18 @@
; RUN: llc < %s -mtriple=arm-apple-ios5.0 -mcpu=cortex-a8 | FileCheck %s
; RUN: llc < %s -mtriple=arm-apple-ios5.0 -mcpu=cortex-a8 | FileCheck %s -check-prefix=A8
; RUN: llc < %s -mtriple=arm-apple-ios5.0 -mcpu=swift | FileCheck %s -check-prefix=SWIFT
; rdar://12481395
define void @foo(i32 %x, i32 %y, i32* nocapture %P) nounwind ssp {
entry:
; CHECK: foo:
; CHECK: bl ___divmodsi4
; CHECK-NOT: bl ___divmodsi4
; A8: foo:
; A8: bl ___divmodsi4
; A8-NOT: bl ___divmodsi4
; SWIFT: foo:
; SWIFT: sdiv
; SWIFT: mls
; SWIFT-NOT: bl __divmodsi4
%div = sdiv i32 %x, %y
store i32 %div, i32* %P, align 4
%rem = srem i32 %x, %y
@ -15,9 +23,14 @@ entry:
define void @bar(i32 %x, i32 %y, i32* nocapture %P) nounwind ssp {
entry:
; CHECK: bar:
; CHECK: bl ___udivmodsi4
; CHECK-NOT: bl ___udivmodsi4
; A8: bar:
; A8: bl ___udivmodsi4
; A8-NOT: bl ___udivmodsi4
; SWIFT: bar:
; SWIFT: udiv
; SWIFT: mls
; SWIFT-NOT: bl __udivmodsi4
%div = udiv i32 %x, %y
store i32 %div, i32* %P, align 4
%rem = urem i32 %x, %y
@ -32,14 +45,18 @@ entry:
define void @do_indent(i32 %cols) nounwind {
entry:
; CHECK: do_indent:
; A8: do_indent:
; SWIFT: do_indent:
%0 = load i32* @flags, align 4
%1 = and i32 %0, 67108864
%2 = icmp eq i32 %1, 0
br i1 %2, label %bb1, label %bb
bb:
; CHECK: bl ___divmodsi4
; A8: bl ___divmodsi4
; SWIFT: sdiv
; SWIFT: mls
; SWIFT-NOT: bl __divmodsi4
%3 = load i32* @tabsize, align 4
%4 = srem i32 %cols, %3
%5 = sdiv i32 %cols, %3
@ -60,9 +77,14 @@ declare i8* @__memset_chk(i8*, i32, i32, i32) nounwind
; rdar://11714607
define i32 @howmany(i32 %x, i32 %y) nounwind {
entry:
; CHECK: howmany:
; CHECK: bl ___udivmodsi4
; CHECK-NOT: ___udivsi3
; A8: howmany:
; A8: bl ___udivmodsi4
; A8-NOT: ___udivsi3
; SWIFT: howmany:
; SWIFT: udiv
; SWIFT: mls
; SWIFT-NOT: bl __udivmodsi4
%rem = urem i32 %x, %y
%div = udiv i32 %x, %y
%not.cmp = icmp ne i32 %rem, 0