Don't use INSERT_SUBREG to model anyext operations on x86-64, as it

leads to partial-register definitions. To help avoid redundant
zero-extensions, also teach the h-register matching patterns that
use movzbl to match anyext as well as zext.

llvm-svn: 80099

llvm/lib/Target/X86/X86Instr64bit.td

@@ -1599,30 +1599,15 @@ def : Pat<(extloadi64i16 addr:$src), (MOVZX64rm16 addr:$src)>;
 // For other extloads, use subregs, since the high contents of the register are
 // defined after an extload.
 def : Pat<(extloadi64i32 addr:$src),
-          (INSERT_SUBREG (i64 (IMPLICIT_DEF)), (MOV32rm addr:$src),
+          (SUBREG_TO_REG (i64 0), (MOV32rm addr:$src),
                          x86_subreg_32bit)>;
-def : Pat<(extloadi16i1 addr:$src), 
-          (INSERT_SUBREG (i16 (IMPLICIT_DEF)), (MOV8rm addr:$src), 
-                         x86_subreg_8bit)>,
-         Requires<[In64BitMode]>;
-def : Pat<(extloadi16i8 addr:$src), 
-          (INSERT_SUBREG (i16 (IMPLICIT_DEF)), (MOV8rm addr:$src), 
-                         x86_subreg_8bit)>,
-         Requires<[In64BitMode]>;
 
-// anyext
+// anyext. Define these to do an explicit zero-extend to
-def : Pat<(i64 (anyext GR8:$src)),
+// avoid partial-register updates.
-          (INSERT_SUBREG (i64 (IMPLICIT_DEF)), GR8:$src, x86_subreg_8bit)>;
+def : Pat<(i64 (anyext GR8 :$src)), (MOVZX64rr8  GR8  :$src)>;
-def : Pat<(i64 (anyext GR16:$src)),
+def : Pat<(i64 (anyext GR16:$src)), (MOVZX64rr16 GR16 :$src)>;
-          (INSERT_SUBREG (i64 (IMPLICIT_DEF)), GR16:$src, x86_subreg_16bit)>;
 def : Pat<(i64 (anyext GR32:$src)),
-          (INSERT_SUBREG (i64 (IMPLICIT_DEF)), GR32:$src, x86_subreg_32bit)>;
+          (SUBREG_TO_REG (i64 0), GR32:$src, x86_subreg_32bit)>;
-def : Pat<(i16 (anyext GR8:$src)),
-          (INSERT_SUBREG (i16 (IMPLICIT_DEF)), GR8:$src, x86_subreg_8bit)>,
-         Requires<[In64BitMode]>;
-def : Pat<(i32 (anyext GR8:$src)),
-          (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR8:$src, x86_subreg_8bit)>,
-         Requires<[In64BitMode]>;
 
 //===----------------------------------------------------------------------===//
 // Some peepholes
@@ -1720,6 +1705,11 @@ def : Pat<(i32 (zext (srl_su GR16:$src, (i8 8)))),
             (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                             x86_subreg_8bit_hi))>,
       Requires<[In64BitMode]>;
+def : Pat<(i32 (anyext (srl_su GR16:$src, (i8 8)))),
+          (MOVZX32_NOREXrr8
+            (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
+                            x86_subreg_8bit_hi))>,
+      Requires<[In64BitMode]>;
 def : Pat<(i64 (zext (srl_su GR16:$src, (i8 8)))),
           (SUBREG_TO_REG
             (i64 0),
@@ -1727,6 +1717,13 @@ def : Pat<(i64 (zext (srl_su GR16:$src, (i8 8)))),
               (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                               x86_subreg_8bit_hi)),
             x86_subreg_32bit)>;
+def : Pat<(i64 (anyext (srl_su GR16:$src, (i8 8)))),
+          (SUBREG_TO_REG
+            (i64 0),
+            (MOVZX32_NOREXrr8
+              (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
+                              x86_subreg_8bit_hi)),
+            x86_subreg_32bit)>;
 
 // h-register extract and store.
 def : Pat<(store (i8 (trunc_su (srl_su GR64:$src, (i8 8)))), addr:$dst),

llvm/lib/Target/X86/X86InstrInfo.td

@@ -3630,21 +3630,17 @@ def : Pat<(zextloadi32i1 addr:$src), (MOVZX32rm8 addr:$src)>;
 
 // extload bool -> extload byte
 def : Pat<(extloadi8i1 addr:$src),   (MOV8rm      addr:$src)>;
-def : Pat<(extloadi16i1 addr:$src),  (MOVZX16rm8  addr:$src)>,
+def : Pat<(extloadi16i1 addr:$src),  (MOVZX16rm8  addr:$src)>;
-         Requires<[In32BitMode]>;
 def : Pat<(extloadi32i1 addr:$src),  (MOVZX32rm8  addr:$src)>;
-def : Pat<(extloadi16i8 addr:$src),  (MOVZX16rm8  addr:$src)>,
+def : Pat<(extloadi16i8 addr:$src),  (MOVZX16rm8  addr:$src)>;
-         Requires<[In32BitMode]>;
 def : Pat<(extloadi32i8 addr:$src),  (MOVZX32rm8  addr:$src)>;
 def : Pat<(extloadi32i16 addr:$src), (MOVZX32rm16 addr:$src)>;
 
-// anyext
+// anyext. Define these to do an explicit zero-extend to
-def : Pat<(i16 (anyext GR8 :$src)), (MOVZX16rr8  GR8 :$src)>,
+// avoid partial-register updates.
-         Requires<[In32BitMode]>;
+def : Pat<(i16 (anyext GR8 :$src)), (MOVZX16rr8  GR8 :$src)>;
-def : Pat<(i32 (anyext GR8 :$src)), (MOVZX32rr8  GR8 :$src)>,
+def : Pat<(i32 (anyext GR8 :$src)), (MOVZX32rr8  GR8 :$src)>;
-         Requires<[In32BitMode]>;
+def : Pat<(i32 (anyext GR16:$src)), (MOVZX32rr16 GR16:$src)>;
-def : Pat<(i32 (anyext GR16:$src)),
-          (INSERT_SUBREG (i32 (IMPLICIT_DEF)), GR16:$src, x86_subreg_16bit)>;
 
 // (and (i32 load), 255) -> (zextload i8)
 def : Pat<(i32 (and (nvloadi32 addr:$src), (i32 255))),
@@ -3725,6 +3721,10 @@ def : Pat<(i32 (zext (srl_su GR16:$src, (i8 8)))),
           (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
                                       x86_subreg_8bit_hi))>,
       Requires<[In32BitMode]>;
+def : Pat<(i32 (anyext (srl_su GR16:$src, (i8 8)))),
+          (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR16:$src, GR16_ABCD),
+                                      x86_subreg_8bit_hi))>,
+      Requires<[In32BitMode]>;
 def : Pat<(and (srl_su GR32:$src, (i8 8)), (i32 255)),
           (MOVZX32rr8 (EXTRACT_SUBREG (COPY_TO_REGCLASS GR32:$src, GR32_ABCD),
                                       x86_subreg_8bit_hi))>,

llvm/test/CodeGen/X86/anyext.ll

@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep movzbl | count 2
+
+; Use movzbl to avoid partial-register updates.
+
+define i32 @foo(i32 %p, i8 zeroext %x) nounwind {
+  %q = trunc i32 %p to i8
+  %r = udiv i8 %q, %x
+  %s = zext i8 %r to i32
+  %t = and i32 %s, 1
+  ret i32 %t
+}
+define i32 @bar(i32 %p, i16 zeroext %x) nounwind {
+  %q = trunc i32 %p to i16
+  %r = udiv i16 %q, %x
+  %s = zext i16 %r to i32
+  %t = and i32 %s, 1
+  ret i32 %t
+}

llvm/test/CodeGen/X86/ins_subreg_coalesce-1.ll

@@ -1,4 +1,4 @@
-; RUN: llvm-as < %s | llc -march=x86 | grep mov | count 2
+; RUN: llvm-as < %s | llc -march=x86 | grep mov | count 3
 
 define fastcc i32 @sqlite3ExprResolveNames() nounwind  {
 entry: