[llvm] r274855 - Do not expand SDIV when compiling for minimum code size
Sjoerd Meijer via llvm-commits
llvm-commits at lists.llvm.org
Fri Jul 8 08:32:01 PDT 2016
Author: sjoerdmeijer
Date: Fri Jul 8 10:32:01 2016
New Revision: 274855
URL: http://llvm.org/viewvc/llvm-project?rev=274855&view=rev
Log:
Do not expand SDIV when compiling for minimum code size
Differential Revision: http://reviews.llvm.org/D22139
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/test/CodeGen/ARM/urem-opt-size.ll
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=274855&r1=274854&r2=274855&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Fri Jul 8 10:32:01 2016
@@ -14475,6 +14475,11 @@ SDValue DAGCombiner::SimplifySetCC(EVT V
/// by a magic number.
/// Ref: "Hacker's Delight" or "The PowerPC Compiler Writer's Guide".
SDValue DAGCombiner::BuildSDIV(SDNode *N) {
+ // when optimising for minimum size, we don't want to expand a div to a mul
+ // and a shift.
+ if (DAG.getMachineFunction().getFunction()->optForMinSize())
+ return SDValue();
+
ConstantSDNode *C = isConstOrConstSplat(N->getOperand(1));
if (!C)
return SDValue();
Modified: llvm/trunk/test/CodeGen/ARM/urem-opt-size.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/urem-opt-size.ll?rev=274855&r1=274854&r2=274855&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/urem-opt-size.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/urem-opt-size.ll Fri Jul 8 10:32:01 2016
@@ -1,5 +1,5 @@
-; When optimising for minimum size, we don't want to expand a udiv to a mul
-; and a shift sequence. As a result, the urem instruction will not be
+; When optimising for minimum size, we don't want to expand a div to a mul
+; and a shift sequence. As a result, the urem instruction e.g. will not be
; expanded to a sequence of umull, lsrs, muls and sub instructions, but
; just a call to __aeabi_uidivmod.
;
@@ -8,9 +8,29 @@
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv7m-arm-none-eabi"
-define i32 @foo() local_unnamed_addr #0 {
+define i32 @foo1() local_unnamed_addr #0 {
entry:
-; CHECK-LABEL: foo:
+; CHECK-LABEL: foo1:
+; CHECK:__aeabi_idiv
+; CHECK-NOT: smmul
+ %call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)()
+ %div = sdiv i32 %call, 1000000
+ ret i32 %div
+}
+
+define i32 @foo2() local_unnamed_addr #0 {
+entry:
+; CHECK-LABEL: foo2:
+; CHECK: __aeabi_uidiv
+; CHECK-NOT: umull
+ %call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)()
+ %div = udiv i32 %call, 1000000
+ ret i32 %div
+}
+
+define i32 @foo3() local_unnamed_addr #0 {
+entry:
+; CHECK-LABEL: foo3:
; CHECK: __aeabi_uidivmod
; CHECK-NOT: umull
%call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)()
More information about the llvm-commits
mailing list