; 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. ; ; When the processor features hardware division, UDIV + UREM can be turned ; into UDIV + MLS. This prevents the library function __aeabi_uidivmod to be ; pulled into the binary. The test uses ARMv7-M. ; ; RUN: llc -mtriple=armv7a-eabi -mattr=-neon -verify-machineinstrs %s -o - | FileCheck %s ; RUN: llc -mtriple=thumbv7m-eabi -verify-machineinstrs %s -o - | FileCheck %s -check-prefix=V7M 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 @foo1() local_unnamed_addr #0 { entry: ; 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 } ; Test for unsigned remainder define i32 @foo3() local_unnamed_addr #0 { entry: ; CHECK-LABEL: foo3: ; CHECK: __aeabi_uidivmod ; CHECK-NOT: umull ; V7M-LABEL: foo3: ; V7M: udiv [[R2:r[0-9]+]], [[R0:r[0-9]+]], [[R1:r[0-9]+]] ; V7M: mls {{r[0-9]+}}, [[R2]], [[R1]], [[R0]] ; V7M-NOT: __aeabi_uidivmod %call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)() %rem = urem i32 %call, 1000000 %cmp = icmp eq i32 %rem, 0 %conv = zext i1 %cmp to i32 ret i32 %conv } ; Test for signed remainder define i32 @foo4() local_unnamed_addr #0 { entry: ; CHECK-LABEL: foo4: ; CHECK:__aeabi_idivmod ; V7M-LABEL: foo4: ; V7M: sdiv [[R2:r[0-9]+]], [[R0:r[0-9]+]], [[R1:r[0-9]+]] ; V7M: mls {{r[0-9]+}}, [[R2]], [[R1]], [[R0]] ; V7M-NOT: __aeabi_idivmod %call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)() %rem = srem i32 %call, 1000000 ret i32 %rem } ; Check that doing a sdiv+srem has the same effect as only the srem, ; as the division needs to be computed anyway in order to calculate ; the remainder (i.e. make sure we don't end up with two divisions). define i32 @foo5() local_unnamed_addr #0 { entry: ; CHECK-LABEL: foo5: ; CHECK:__aeabi_idivmod ; V7M-LABEL: foo5: ; V7M: sdiv [[R2:r[0-9]+]], [[R0:r[0-9]+]], [[R1:r[0-9]+]] ; V7M-NOT: sdiv ; V7M: mls {{r[0-9]+}}, [[R2]], [[R1]], [[R0]] ; V7M-NOT: __aeabi_idivmod %call = tail call i32 bitcast (i32 (...)* @GetValue to i32 ()*)() %div = sdiv i32 %call, 1000000 %rem = srem i32 %call, 1000000 %add = add i32 %div, %rem ret i32 %add } ; An early version of this patch caused isel to hang. The reason ; was that it shouldn't do the rewrite for i64 because that's not ; supported by hardware. Isel was stuck in a loop with type ; legalization and this optimisation. ; Function Attrs: norecurse nounwind define i64 @isel_dont_hang(i32 %bar) local_unnamed_addr #4 { entry: ; CHECK-LABEL: isel_dont_hang: ; CHECK: __aeabi_uldivmod %temp.0 = sext i32 %bar to i64 %mul83 = shl i64 %temp.0, 1 %add84 = add i64 %temp.0, 2 %div85 = udiv i64 %mul83, %add84 ret i64 %div85 } ; i16 types are promoted to i32, and we expect a normal udiv here: define i16 @isel_dont_hang_2(i16 %bar) local_unnamed_addr #4 { entry: ; CHECK-LABEL: isel_dont_hang_2: ; CHECK: udiv ; CHECK-NOT: __aeabi_ %mul83 = shl i16 %bar, 1 %add84 = add i16 %bar, 2 %div85 = udiv i16 %mul83, %add84 ret i16 %div85 } declare i32 @GetValue(...) local_unnamed_addr attributes #0 = { minsize nounwind optsize } attributes #4 = { norecurse nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-jump-tables"="false" "stack-protector-buffer-size"="8" "target-cpu"="cortex-a15" "target-features"="+dsp,+hwdiv,+hwdiv-arm,+neon,+vfp4" "use-soft-float"="false" }