[CodeGen] Always expand division larger than i128

Default MaxDivRemBitWidthSupported to 128, so that divisions larger
than 128 bits are always expanded, without requiring additional
configuration from the target.

Note that this may still emit calls to __udivti3 on 32-bit targets,
which likely don't have an implementation of that builtin. However,
I believe this is sufficient to fix
#60531, because Zig must
already be defining those builtins.

Differential Revision: https://reviews.llvm.org/D144871

(cherry picked from commit ddccc5b)

Author: nikic

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -724,7 +724,9 @@ TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm) : TM(tm) {
   // with the Target-specific changes necessary.
   MaxAtomicSizeInBitsSupported = 1024;
 
-  MaxDivRemBitWidthSupported = llvm::IntegerType::MAX_INT_BITS;
+  // Assume that even with libcalls, no target supports wider than 128 bit
+  // division.
+  MaxDivRemBitWidthSupported = 128;
 
   MaxLargeFPConvertBitWidthSupported = llvm::IntegerType::MAX_INT_BITS;
 

llvm/test/CodeGen/Mips/idiv_large.ll

@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=mips-- < %s | FileCheck %s
+; RUN: llc -mtriple=mips64-- < %s | FileCheck %s
+
+define i128 @udiv_i128(i128 %x, i128 %y) nounwind {
+; CHECK-LABEL: udiv_i128:
+; CHECK:    jal __udivti3
+  %res = udiv i128 %x, %y
+  ret i128 %res
+}
+
+define i129 @udiv_i129(i129 %x, i129 %y) nounwind {
+; CHECK-LABEL: udiv_i129:
+; CHECK-NOT: jal
+  %res = udiv i129 %x, %y
+  ret i129 %res
+}

llvm/test/CodeGen/PowerPC/idiv_large.ll

@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=powerpc-- < %s | FileCheck %s
+; RUN: llc -mtriple=powerpc64-- < %s | FileCheck %s
+
+define i128 @udiv_i128(i128 %x, i128 %y) nounwind {
+; CHECK-LABEL: udiv_i128:
+; CHECK:    bl __udivti3
+  %res = udiv i128 %x, %y
+  ret i128 %res
+}
+
+define i129 @udiv_i129(i129 %x, i129 %y) nounwind {
+; CHECK-LABEL: udiv_i129:
+; CHECK-NOT: bl __
+  %res = udiv i129 %x, %y
+  ret i129 %res
+}

llvm/test/CodeGen/RISCV/idiv_large.ll

@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 < %s | FileCheck %s
+; RUN: llc -mtriple=riscv64 < %s | FileCheck %s
+
+define i128 @udiv_i128(i128 %x, i128 %y) nounwind {
+; CHECK-LABEL: udiv_i128:
+; CHECK:    call __udivti3
+  %res = udiv i128 %x, %y
+  ret i128 %res
+}
+
+define i129 @udiv_i129(i129 %x, i129 %y) nounwind {
+; CHECK-LABEL: udiv_i129:
+; CHECK-NOT: call{{.*}}div
+  %res = udiv i129 %x, %y
+  ret i129 %res
+}