[llvm] r270096 - [x86] add tests for urem lowering

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Thu May 19 13:57:54 2016
New Revision: 270096

URL: http://llvm.org/viewvc/llvm-project?rev=270096&view=rev
Log:
[x86] add tests for urem lowering

Added:
    llvm/trunk/test/CodeGen/X86/urem-power-of-two.ll

Added: llvm/trunk/test/CodeGen/X86/urem-power-of-two.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/urem-power-of-two.ll?rev=270096&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/urem-power-of-two.ll (added)
+++ llvm/trunk/test/CodeGen/X86/urem-power-of-two.ll Thu May 19 13:57:54 2016
@@ -0,0 +1,80 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
+
+; The easy case: a constant power-of-2 divisor.
+
+define i64 @const_pow_2(i64 %x) {
+; CHECK-LABEL: const_pow_2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    andl $31, %edi
+; CHECK-NEXT:    movq %rdi, %rax
+; CHECK-NEXT:    retq
+;
+  %urem = urem i64 %x, 32
+  ret i64 %urem
+}
+
+; A left-shifted power-of-2 divisor. Use a weird type for wider coverage.
+
+define i25 @shift_left_pow_2(i25 %x, i25 %y) {
+; CHECK-LABEL: shift_left_pow_2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    movl $1, %eax
+; CHECK-NEXT:    movl %esi, %ecx
+; CHECK-NEXT:    shll %cl, %eax
+; CHECK-NEXT:    addl $33554431, %eax # imm = 0x1FFFFFF
+; CHECK-NEXT:    andl %edi, %eax
+; CHECK-NEXT:    retq
+;
+  %shl = shl i25 1, %y
+  %urem = urem i25 %x, %shl
+  ret i25 %urem
+}
+
+; FIXME: A logically right-shifted sign bit is a power-of-2 or UB.
+
+define i16 @shift_right_pow_2(i16 %x, i16 %y) {
+; CHECK-LABEL: shift_right_pow_2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    movl $32768, %r8d # imm = 0x8000
+; CHECK-NEXT:    movl %esi, %ecx
+; CHECK-NEXT:    shrl %cl, %r8d
+; CHECK-NEXT:    xorl %edx, %edx
+; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    divw %r8w
+; CHECK-NEXT:    movl %edx, %eax
+; CHECK-NEXT:    retq
+;
+  %shr = lshr i16 -32768, %y
+  %urem = urem i16 %x, %shr
+  ret i16 %urem
+}
+
+; FIXME: A zero divisor would be UB, so this could be reduced to an 'and' with 3.
+
+define i8 @and_pow_2(i8 %x, i8 %y) {
+; CHECK-LABEL: and_pow_2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    andb $4, %sil
+; CHECK-NEXT:    movzbl %dil, %eax
+; CHECK-NEXT:    divb %sil
+; CHECK-NEXT:    movzbl %ah, %eax # NOREX
+; CHECK-NEXT:    retq
+;
+  %and = and i8 %y, 4
+  %urem = urem i8 %x, %and
+  ret i8 %urem
+}
+
+; A vector splat constant divisor should get the same treatment as a scalar. 
+
+define <4 x i32> @vec_const_pow_2(<4 x i32> %x) {
+; CHECK-LABEL: vec_const_pow_2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    andps {{.*}}(%rip), %xmm0
+; CHECK-NEXT:    retq
+;
+  %urem = urem <4 x i32> %x, <i32 16, i32 16, i32 16, i32 16>
+  ret <4 x i32> %urem
+}
+