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Do not expand SDIV when compiling for minimum code size

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Differential Revision: http://reviews.llvm.org/D22139

llvm-svn: 274855
This commit is contained in:
Sjoerd Meijer 2016-07-08 15:32:01 +00:00
parent e3fa3bfe94
commit 22394dc4fc
2 changed files with 29 additions and 4 deletions
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5
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -14475,6 +14475,11 @@ SDValue DAGCombiner::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
/// 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();

28
test/CodeGen/ARM/urem-opt-size.ll
View File

@ -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 ()*)()