[SystemZ] Add negative integer absolute (load negative)

For now this matches the equivalent of (neg (abs ...)), which did hit a few
times in projects/test-suite.  We should probably also match cases where
absolute-like selects are used with reversed arguments.

llvm-svn: 188671

3 files changed, 12 insertions, 6 deletions

diff --git a/llvm/lib/Target/SystemZ/README.txt b/llvm/lib/Target/SystemZ/README.txt
index 93e29b8a0fa..58e631f88c0 100644
--- a/llvm/lib/Target/SystemZ/README.txt
+++ b/llvm/lib/Target/SystemZ/README.txt
@@ -104,12 +104,6 @@ such as ICM and STCM.
 
 --
 
-DAGCombiner can detect integer absolute, but there's not yet an associated
-ISD opcode.  We could add one and implement it using LOAD POSITIVE.
-Negated absolutes could use LOAD NEGATIVE.
-
---
-
 DAGCombiner doesn't yet fold truncations of extended loads.  Functions like:
 
     unsigned long f (unsigned long x, unsigned short *y)
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
index dd3a9bca088..d857a572fb9 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.td
@@ -549,6 +549,16 @@ defm : SXU<z_iabs64, LPGFR>;
 
 let Defs = [CC] in {
   let CCValues = 0xF, CompareZeroCCMask = 0x8 in {
+    def LNR  : UnaryRR <"ln",  0x11,   z_inegabs32, GR32, GR32>;
+    def LNGR : UnaryRRE<"lng", 0xB901, z_inegabs64, GR64, GR64>;
+  }
+  let CCValues = 0xE, CompareZeroCCMask = 0xE in
+    def LNGFR : UnaryRRE<"lngf", 0xB911, null_frag, GR64, GR32>;
+}
+defm : SXU<z_inegabs64, LNGFR>;
+
+let Defs = [CC] in {
+  let CCValues = 0xF, CompareZeroCCMask = 0x8 in {
     def LCR  : UnaryRR <"lc",  0x13,   ineg, GR32, GR32>;
     def LCGR : UnaryRRE<"lcg", 0xB903, ineg, GR64, GR64>;
   }
diff --git a/llvm/lib/Target/SystemZ/SystemZOperators.td b/llvm/lib/Target/SystemZ/SystemZOperators.td
index 59e1ffcfcfa..5745e29cd8f 100644
--- a/llvm/lib/Target/SystemZ/SystemZOperators.td
+++ b/llvm/lib/Target/SystemZ/SystemZOperators.td
@@ -247,6 +247,8 @@ def z_iabs32 : PatFrag<(ops node:$src),
 def z_iabs64 : PatFrag<(ops node:$src),
                        (xor (add node:$src, (sra node:$src, (i32 63))),
                             (sra node:$src, (i32 63)))>;
+def z_inegabs32 : PatFrag<(ops node:$src), (ineg (z_iabs32 node:$src))>;
+def z_inegabs64 : PatFrag<(ops node:$src), (ineg (z_iabs64 node:$src))>;
 
 // Fused multiply-add and multiply-subtract, but with the order of the
 // operands matching SystemZ's MA and MS instructions.