[ARM] Honour ABI for rem under -O0 for EABI, GNUEABI, Android and Musl

At higher optimization levels, we generate the libcall for DIVREM_Ix, which is
fine: aeabi_{u|i}divmod. At -O0 we generate the one for REM_Ix, which is the
default {u}mod{q|h|s|d}i3.

This commit makes sure that we don't generate REM_Ix calls for ABIs that
don't support them (i.e. where we need to use DIVREM_Ix instead). This is
achieved by bailing out of FastISel, which can't handle non-double multi-reg
returns, and letting the legalization infrastructure expand the REM_Ix calls.

It also updates the divmod-eabi.ll test to run under -O0 as well, and adds some
Windows checks to it to make sure we don't break things for it.

Fixes PR27068

Differential Revision: https://reviews.llvm.org/D21926

llvm-svn: 275773

1 files changed, 105 insertions, 12 deletions

diff --git a/llvm/test/CodeGen/ARM/divmod-eabi.ll b/llvm/test/CodeGen/ARM/divmod-eabi.ll
index 748794f2fa5..1e4c8fc336d 100644
--- a/llvm/test/CodeGen/ARM/divmod-eabi.ll
+++ b/llvm/test/CodeGen/ARM/divmod-eabi.ll
@@ -1,16 +1,33 @@
+; We run the tests with both the default optimization level and O0, to make sure
+; we don't have any ABI differences between them. In principle, the ABI checks
+; should be the same for both optimization levels (there could be exceptions
+; from this when a div and a mod with the same operands are not coallesced into
+; the same divmod, but luckily this doesn't occur in practice even at O0).
+; Sometimes the checks that the correct registers are used after the libcalls
+; are different between optimization levels, so we have to separate them.
 ; RUN: llc -mtriple armv7-none-eabi %s -o - | FileCheck %s --check-prefix=EABI
+; RUN: llc -mtriple armv7-none-eabi %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefix=EABI
 ; RUN: llc -mtriple armv7-none-eabihf %s -o - | FileCheck %s --check-prefix=EABI
+; RUN: llc -mtriple armv7-none-eabihf %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefix=EABI
 ; All "eabi" (Bare, GNU and Android) must lower SREM/UREM to __aeabi_{u,i}divmod
 ; RUN: llc -mtriple armv7-linux-androideabi %s -o - | FileCheck %s --check-prefix=EABI
+; RUN: llc -mtriple armv7-linux-androideabi %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefix=EABI
 ; RUN: llc -mtriple armv7-linux-gnueabi %s -o - | FileCheck %s --check-prefix=EABI
+; RUN: llc -mtriple armv7-linux-gnueabi %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefix=EABI
 ; RUN: llc -mtriple armv7-linux-musleabi %s -o - | FileCheck %s --check-prefix=EABI
-; RUN: llc -mtriple armv7-apple-darwin %s -o - | FileCheck %s --check-prefix=DARWIN
+; RUN: llc -mtriple armv7-linux-musleabi %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefix=EABI
+; RUN: llc -mtriple armv7-apple-darwin %s -o - | FileCheck %s --check-prefixes=DARWIN,DARWIN-DEFAULT
+; RUN: llc -mtriple armv7-apple-darwin %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefixes=DARWIN,DARWIN-O0
 ; FIXME: long-term, we will use "-apple-macho" and won't need this exception:
-; RUN: llc -mtriple armv7-apple-darwin-eabi %s -o - | FileCheck %s --check-prefix=DARWIN
+; RUN: llc -mtriple armv7-apple-darwin-eabi %s -o - | FileCheck %s --check-prefixes=DARWIN,DARWIN-DEFAULT
+; RUN: llc -mtriple armv7-apple-darwin-eabi %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefixes=DARWIN,DARWIN-O0
+; RUN: llc -mtriple thumbv7-windows %s -o - | FileCheck %s --check-prefixes=WINDOWS,WINDOWS-DEFAULT
+; RUN: llc -mtriple thumbv7-windows %s -o - -O0 -optimize-regalloc | FileCheck %s --check-prefixes=WINDOWS,WINDOWS-O0
 
 define signext i16 @f16(i16 signext %a, i16 signext %b) {
 ; EABI-LABEL: f16:
 ; DARWIN-LABEL: f16:
+; WINDOWS-LABEL: f16:
 entry:
   %conv = sext i16 %a to i32
   %conv1 = sext i16 %b to i32
@@ -20,25 +37,39 @@ entry:
 ; EABI: mov [[div:r[0-9]+]], r0
 ; EABI: mov [[rem:r[0-9]+]], r1
 ; DARWIN: ___divsi3
-; DARWIN: mov [[sum:r[0-9]+]], r0
+; DARWIN: mov [[div:r[0-9]+]], r0
 ; DARWIN: __modsi3
-; DARWIN: add [[sum]]{{.*}}r0
+; DARWIN-DEFAULT: add [[sum:r[0-9]+]], r0, [[div]]
+; DARWIN-O0: mov [[rem:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS-DEFAULT: mls [[rem:r[0-9]+]], r0,
+; WINDOWS-DEFAULT: adds [[sum:r[0-9]+]], [[rem]], r0
+; WINDOWS-O0: mov [[div:r[0-9]+]], r0
+; WINDOWS-O0: mls [[rem:r[0-9]+]], [[div]],
   %rem8 = srem i32 %conv1, %conv
 ; EABI: __aeabi_idivmod
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem1:r[0-9]+]], r0,
   %add = add nsw i32 %rem, %div
   %add13 = add nsw i32 %add, %rem8
   %conv14 = trunc i32 %add13 to i16
 ; EABI: add r0{{.*}}r1
 ; EABI: sxth r0, r0
-; DARWIN: add r0{{.*}}[[sum]]
-; DARWIN: sxth r0, r0
+; DARWIN-DEFAULT: add [[res:r[0-9]+]], [[sum]], r0
+; DARWIN-O0: add [[sum:r[0-9]+]], [[rem]], [[div]]
+; DARWIN-O0: add [[res:r[0-9]+]], [[sum]], r0
+; DARWIN: sxth r0, [[res]]
+; WINDOWS-O0: adds [[sum:r[0-9]+]], [[rem]], [[div]]
+; WINDOWS: add [[rem1]], [[sum]]
+; WINDOWS: sxth [[res:r[0-9]+]], [[rem1]]
   ret i16 %conv14
 }
 
 define i32 @f32(i32 %a, i32 %b) {
 ; EABI-LABEL: f32:
 ; DARWIN-LABEL: f32:
+; WINDOWS-LABEL: f32:
 entry:
   %div = sdiv i32 %a, %b
   %rem = srem i32 %a, %b
@@ -46,43 +77,71 @@ entry:
 ; EABI: mov [[div:r[0-9]+]], r0
 ; EABI: mov [[rem:r[0-9]+]], r1
 ; DARWIN: ___divsi3
-; DARWIN: mov [[sum:r[0-9]+]], r0
+; DARWIN: mov [[div:r[0-9]+]], r0
 ; DARWIN: __modsi3
-; DARWIN: add [[sum]]{{.*}}r0
+; DARWIN-DEFAULT: add [[sum:r[0-9]+]], r0, [[div]]
+; DARWIN-O0: mov [[rem:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mov [[div:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
+; WINDOWS-DEFAULT: add [[div]], [[rem]]
   %rem1 = srem i32 %b, %a
 ; EABI: __aeabi_idivmod
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem1:r[0-9]+]], r0,
   %add = add nsw i32 %rem, %div
   %add2 = add nsw i32 %add, %rem1
 ; EABI: add r0{{.*}}r1
-; DARWIN: add r0{{.*}}[[sum]]
+; DARWIN-DEFAULT: add r0, [[sum]], r0
+; DARWIN-O0: add [[sum:r[0-9]+]], [[rem]], [[div]]
+; DARWIN-O0: add [[res:r[0-9]+]], [[sum]], r0
+; WINDOWS-DEFAULT: add [[rem1]], [[div]]
+; WINDOWS-O0: adds [[sum:r[0-9]+]], [[rem]], [[div]]
+; WINDOWS-O0: add [[rem1]], [[sum]]
   ret i32 %add2
 }
 
 define i32 @uf(i32 %a, i32 %b) {
 ; EABI-LABEL: uf:
 ; DARWIN-LABEL: uf:
+; WINDOWS-LABEL: uf:
 entry:
   %div = udiv i32 %a, %b
   %rem = urem i32 %a, %b
 ; EABI: __aeabi_uidivmod
 ; DARWIN: ___udivsi3
-; DARWIN: mov [[sum:r[0-9]+]], r0
+; DARWIN: mov [[div:r[0-9]+]], r0
 ; DARWIN: __umodsi3
-; DARWIN: add [[sum]]{{.*}}r0
+; DARWIN-DEFAULT: add [[sum:r[0-9]+]], r0, [[div]]
+; DARWIN-O0: mov [[rem:r[0-9]+]], r0
+; WINDOWS: __rt_udiv
+; WINDOWS: mov [[div:r[0-9]+]], r0
+; WINDOWS: __rt_udiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
+; WINDOWS-DEFAULT: add [[div]], [[rem]]
   %rem1 = urem i32 %b, %a
 ; EABI: __aeabi_uidivmod
 ; DARWIN: __umodsi3
+; WINDOWS: __rt_udiv
+; WINDOWS: mls [[rem1:r[0-9]+]], r0,
   %add = add nuw i32 %rem, %div
   %add2 = add nuw i32 %add, %rem1
 ; EABI: add r0{{.*}}r1
-; DARWIN: add r0{{.*}}[[sum]]
+; DARWIN-DEFAULT: add r0, [[sum]], r0
+; DARWIN-O0: add [[sum:r[0-9]+]], [[rem]], [[div]]
+; DARWIN-O0: add [[res:r[0-9]+]], [[sum]], r0
+; WINDOWS-DEFAULT: add [[rem1]], [[div]]
+; WINDOWS-O0: adds [[sum:r[0-9]+]], [[rem]], [[div]]
+; WINDOWS-O0: add [[rem1]], [[sum]]
   ret i32 %add2
 }
 
 define i64 @longf(i64 %a, i64 %b) {
 ; EABI-LABEL: longf:
 ; DARWIN-LABEL: longf:
+; WINDOWS-LABEL: longf:
 entry:
   %div = sdiv i64 %a, %b
   %rem = srem i64 %a, %b
@@ -94,15 +153,22 @@ entry:
 ; DARWIN: mov [[div1:r[0-9]+]], r0
 ; DARWIN: mov [[div2:r[0-9]+]], r1
 ; DARWIN: __moddi3
+; WINDOWS: __rt_sdiv64
+; WINDOWS: mov [[div1:r[0-9]+]], r0
+; WINDOWS: mov [[div2:r[0-9]+]], r1
+; WINDOWS: __moddi3
   %add = add nsw i64 %rem, %div
 ; DARWIN: adds r0{{.*}}[[div1]]
 ; DARWIN: adc r1{{.*}}[[div2]]
+; WINDOWS: adds.w r0, r0, [[div1]]
+; WINDOWS: adc.w r1, r1, [[div2]]
   ret i64 %add
 }
 
 define i16 @shortf(i16 %a, i16 %b) {
 ; EABI-LABEL: shortf:
 ; DARWIN-LABEL: shortf:
+; WINDOWS-LABEL: shortf:
 entry:
   %div = sdiv i16 %a, %b
   %rem = srem i16 %a, %b
@@ -110,14 +176,21 @@ entry:
 ; DARWIN: ___divsi3
 ; DARWIN: mov [[div1:r[0-9]+]], r0
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mov [[div:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
   %add = add nsw i16 %rem, %div
+; EABI: add r0, r1
 ; DARWIN: add r0{{.*}}[[div1]]
+; WINDOWS: add [[rem]], [[div]]
   ret i16 %add
 }
 
 define i32 @g1(i32 %a, i32 %b) {
 ; EABI-LABEL: g1:
 ; DARWIN-LABEL: g1:
+; WINDOWS-LABEL: g1:
 entry:
   %div = sdiv i32 %a, %b
   %rem = srem i32 %a, %b
@@ -125,9 +198,14 @@ entry:
 ; DARWIN: ___divsi3
 ; DARWIN: mov [[sum:r[0-9]+]], r0
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mov [[div:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
   %add = add nsw i32 %rem, %div
 ; EABI:	add	r0{{.*}}r1
 ; DARWIN: add r0{{.*}}[[sum]]
+; WINDOWS: add [[rem]], [[div]]
   ret i32 %add
 }
 
@@ -135,46 +213,61 @@ entry:
 define i32 @g2(i32 %a, i32 %b) {
 ; EABI-LABEL: g2:
 ; DARWIN-LABEL: g2:
+; WINDOWS-LABEL: g2:
 entry:
   %rem = srem i32 %a, %b
 ; EABI: __aeabi_idivmod
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
   ret i32 %rem
 ; EABI:	mov	r0, r1
+; WINDOWS: mls r0, r0,
 }
 
 define i32 @g3(i32 %a, i32 %b) {
 ; EABI-LABEL: g3:
 ; DARWIN-LABEL: g3:
+; WINDOWS-LABEL: g3:
 entry:
   %rem = srem i32 %a, %b
 ; EABI: __aeabi_idivmod
 ; EABI: mov [[mod:r[0-9]+]], r1
 ; DARWIN: __modsi3
 ; DARWIN: mov [[sum:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
   %rem1 = srem i32 %b, %rem
 ; EABI: __aeabi_idivmod
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem1:r[0-9]+]], r0,
   %add = add nsw i32 %rem1, %rem
 ; EABI: add r0, r1, [[mod]]
 ; DARWIN: add r0{{.*}}[[sum]]
+; WINDOWS: add [[rem1]], [[rem]]
   ret i32 %add
 }
 
 define i32 @g4(i32 %a, i32 %b) {
 ; EABI-LABEL: g4:
 ; DARWIN-LABEL: g4:
+; WINDOWS-LABEL: g4:
 entry:
   %div = sdiv i32 %a, %b
 ; EABI: __aeabi_idiv{{$}}
 ; EABI: mov [[div:r[0-9]+]], r0
 ; DARWIN: ___divsi3
 ; DARWIN: mov [[sum:r[0-9]+]], r0
+; WINDOWS: __rt_sdiv
+; WINDOWS: mov [[div:r[0-9]+]], r0
   %rem = srem i32 %b, %div
 ; EABI: __aeabi_idivmod
 ; DARWIN: __modsi3
+; WINDOWS: __rt_sdiv
+; WINDOWS: mls [[rem:r[0-9]+]], r0,
   %add = add nsw i32 %rem, %div
 ; EABI: add r0, r1, [[div]]
 ; DARWIN: add r0{{.*}}[[sum]]
+; WINDOWS: add [[rem]], [[div]]
   ret i32 %add
 }