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authorEvan Cheng <evan.cheng@apple.com>2012-06-21 05:56:05 +0000
committerEvan Cheng <evan.cheng@apple.com>2012-06-21 05:56:05 +0000
commit8ef0968dc230f6fae8fcbd6dc4a5cb9ccc780b6b (patch)
tree4dcacc50d2c34a682fe9314c4b7a5c559e97d1b6
parentb60182e99b97f31756b013022d94fcfb1aa0be73 (diff)
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Emit a single _udivmodsi4 libcall instead of two separate _udivsi3 and
_umodsi3 libcalls if they have the same arguments. This optimization was apparently broken if one of the node was replaced in place. rdar://11714607 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158900 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r--lib/CodeGen/SelectionDAG/LegalizeDAG.cpp12
-rw-r--r--test/CodeGen/ARM/divmod.ll16
2 files changed, 22 insertions, 6 deletions
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index c2972b051f..1f2fe8a8d8 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1930,9 +1930,11 @@ static bool isDivRemLibcallAvailable(SDNode *Node, bool isSigned,
return TLI.getLibcallName(LC) != 0;
}
-/// UseDivRem - Only issue divrem libcall if both quotient and remainder are
+/// useDivRem - Only issue divrem libcall if both quotient and remainder are
/// needed.
-static bool UseDivRem(SDNode *Node, bool isSigned, bool isDIV) {
+static bool useDivRem(SDNode *Node, bool isSigned, bool isDIV) {
+ // The other use might have been replaced with a divrem already.
+ unsigned DivRemOpc = isSigned ? ISD::SDIVREM : ISD::UDIVREM;
unsigned OtherOpcode = 0;
if (isSigned)
OtherOpcode = isDIV ? ISD::SREM : ISD::SDIV;
@@ -1946,7 +1948,7 @@ static bool UseDivRem(SDNode *Node, bool isSigned, bool isDIV) {
SDNode *User = *UI;
if (User == Node)
continue;
- if (User->getOpcode() == OtherOpcode &&
+ if ((User->getOpcode() == OtherOpcode || User->getOpcode() == DivRemOpc) &&
User->getOperand(0) == Op0 &&
User->getOperand(1) == Op1)
return true;
@@ -3092,7 +3094,7 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
Tmp3 = Node->getOperand(1);
if (TLI.isOperationLegalOrCustom(DivRemOpc, VT) ||
(isDivRemLibcallAvailable(Node, isSigned, TLI) &&
- UseDivRem(Node, isSigned, false))) {
+ useDivRem(Node, isSigned, false))) {
Tmp1 = DAG.getNode(DivRemOpc, dl, VTs, Tmp2, Tmp3).getValue(1);
} else if (TLI.isOperationLegalOrCustom(DivOpc, VT)) {
// X % Y -> X-X/Y*Y
@@ -3120,7 +3122,7 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
SDVTList VTs = DAG.getVTList(VT, VT);
if (TLI.isOperationLegalOrCustom(DivRemOpc, VT) ||
(isDivRemLibcallAvailable(Node, isSigned, TLI) &&
- UseDivRem(Node, isSigned, true)))
+ useDivRem(Node, isSigned, true)))
Tmp1 = DAG.getNode(DivRemOpc, dl, VTs, Node->getOperand(0),
Node->getOperand(1));
else if (isSigned)
diff --git a/test/CodeGen/ARM/divmod.ll b/test/CodeGen/ARM/divmod.ll
index 49c4103757..7fbf8f4090 100644
--- a/test/CodeGen/ARM/divmod.ll
+++ b/test/CodeGen/ARM/divmod.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=arm-apple-ios5.0 | FileCheck %s
+; RUN: llc < %s -mtriple=arm-apple-ios5.0 -mcpu=cortex-a8 | FileCheck %s
define void @foo(i32 %x, i32 %y, i32* nocapture %P) nounwind ssp {
entry:
@@ -56,3 +56,17 @@ bb1:
declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readnone
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
+ %rem = urem i32 %x, %y
+ %div = udiv i32 %x, %y
+ %not.cmp = icmp ne i32 %rem, 0
+ %add = zext i1 %not.cmp to i32
+ %cond = add i32 %add, %div
+ ret i32 %cond
+}