[SelectionDAG] Add a signed integer absolute ISD node
Reduced version of D26357 - based on the discussion on llvm-dev about canonicalization of UMIN/UMAX/SMIN/SMAX as well as ABS I've reduced that patch to just the ABS ISD node (with x86/sse support) to improve basic combines and lowering.
ARM/AArch64, Hexagon, PowerPC and NVPTX all have similar instructions allowing us to make this a generic opcode and move away from the hard coded tablegen patterns which makes it tricky to match more complex patterns.
At the moment this patch doesn't attempt legalization as we only create an ABS node if its legal/custom.
Differential Revision: https://reviews.llvm.org/D29639
llvm-svn: 297780
diff --git a/llvm/test/CodeGen/X86/combine-abs.ll b/llvm/test/CodeGen/X86/combine-abs.ll
index 109738d..2d71e4f 100644
--- a/llvm/test/CodeGen/X86/combine-abs.ll
+++ b/llvm/test/CodeGen/X86/combine-abs.ll
@@ -1,13 +1,11 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=+avx2 | FileCheck %s
-; FIXME: Various missed opportunities to simplify integer absolute instructions.
-
; fold (abs c1) -> c2
define <4 x i32> @combine_v4i32_abs_constant() {
; CHECK-LABEL: combine_v4i32_abs_constant:
; CHECK: # BB#0:
-; CHECK-NEXT: vpabsd {{.*}}(%rip), %xmm0
+; CHECK-NEXT: vmovaps {{.*#+}} xmm0 = [0,1,3,2147483648]
; CHECK-NEXT: retq
%1 = call <4 x i32> @llvm.x86.ssse3.pabs.d.128(<4 x i32> <i32 0, i32 -1, i32 3, i32 -2147483648>)
ret <4 x i32> %1
@@ -16,7 +14,7 @@
define <16 x i16> @combine_v16i16_abs_constant() {
; CHECK-LABEL: combine_v16i16_abs_constant:
; CHECK: # BB#0:
-; CHECK-NEXT: vpabsw {{.*}}(%rip), %ymm0
+; CHECK-NEXT: vmovaps {{.*#+}} ymm0 = [0,1,1,3,3,7,7,255,255,4096,4096,32767,32767,32768,32768,0]
; CHECK-NEXT: retq
%1 = call <16 x i16> @llvm.x86.avx2.pabs.w(<16 x i16> <i16 0, i16 1, i16 -1, i16 3, i16 -3, i16 7, i16 -7, i16 255, i16 -255, i16 4096, i16 -4096, i16 32767, i16 -32767, i16 -32768, i16 32768, i16 65536>)
ret <16 x i16> %1
@@ -27,7 +25,6 @@
; CHECK-LABEL: combine_v8i16_abs_abs:
; CHECK: # BB#0:
; CHECK-NEXT: vpabsw %xmm0, %xmm0
-; CHECK-NEXT: vpabsw %xmm0, %xmm0
; CHECK-NEXT: retq
%a1 = call <8 x i16> @llvm.x86.ssse3.pabs.w.128(<8 x i16> %a)
%n2 = sub <8 x i16> zeroinitializer, %a1
@@ -40,7 +37,6 @@
; CHECK-LABEL: combine_v32i8_abs_abs:
; CHECK: # BB#0:
; CHECK-NEXT: vpabsb %ymm0, %ymm0
-; CHECK-NEXT: vpabsb %ymm0, %ymm0
; CHECK-NEXT: retq
%n1 = sub <32 x i8> zeroinitializer, %a
%b1 = icmp slt <32 x i8> %a, zeroinitializer