Re-introduce the 8-bit subreg zext-inreg patterns for x86-32,

this time using MOV32to32_ and MOV16to16_. Thanks to Evan for
suggesting this.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54418 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 25 insertions, 34 deletions

diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index e7bba79bc1..a187f86a10 100644
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -1251,12 +1251,6 @@ def : Pat<(and GR64:$src, 0xffff),
 // r & (2^8-1) ==> movz
 def : Pat<(and GR64:$src, 0xff),
           (MOVZX64rr8 (i8 (EXTRACT_SUBREG GR64:$src, x86_subreg_8bit)))>;
-
-// TODO: The following two patterns could be adapted to apply to x86-32, except
-// that they'll need some way to deal with the fact that in x86-32 not all GPRs
-// have 8-bit subregs. The GR32_ and GR16_ classes are a step in this direction,
-// but they aren't ready for this purpose yet.
-
 // r & (2^8-1) ==> movz
 def : Pat<(and GR32:$src1, 0xff),
            (MOVZX32rr8 (i8 (EXTRACT_SUBREG GR32:$src1, x86_subreg_8bit)))>,
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index bb90f29b0c..c4db588290 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -2774,6 +2774,16 @@ def : Pat<(i32 (and (loadi32 addr:$src), (i32 65535))),(MOVZX32rm16 addr:$src)>;
 // r & (2^16-1) ==> movz
 def : Pat<(and GR32:$src1, 0xffff),
            (MOVZX32rr16 (i16 (EXTRACT_SUBREG GR32:$src1, x86_subreg_16bit)))>;
+// r & (2^8-1) ==> movz
+def : Pat<(and GR32:$src1, 0xff),
+           (MOVZX32rr8 (i8 (EXTRACT_SUBREG (MOV32to32_ GR32:$src1),
+                                           x86_subreg_8bit)))>,
+      Requires<[In32BitMode]>;
+// r & (2^8-1) ==> movz
+def : Pat<(and GR16:$src1, 0xff),
+           (MOVZX16rr8 (i8 (EXTRACT_SUBREG (MOV16to16_ GR16:$src1),
+                                           x86_subreg_8bit)))>,
+      Requires<[In32BitMode]>;
 
 // (shl x, 1) ==> (add x, x)
 def : Pat<(shl GR8 :$src1, (i8 1)), (ADD8rr  GR8 :$src1, GR8 :$src1)>;
diff --git a/test/CodeGen/X86/zext-inreg-0.ll b/test/CodeGen/X86/zext-inreg-0.ll
index 62c651c835..1a734642d0 100644
--- a/test/CodeGen/X86/zext-inreg-0.ll
+++ b/test/CodeGen/X86/zext-inreg-0.ll
@@ -8,11 +8,26 @@
 ; These should use movzbl instead of 'and 255'.
 ; This related to not having a ZERO_EXTEND_REG opcode.
 
+define i32 @a(i32 %d) nounwind  {
+        %e = add i32 %d, 1
+        %retval = and i32 %e, 255
+        ret i32 %retval
+}
+define i32 @b(float %d) nounwind  {
+        %tmp12 = fptoui float %d to i8
+        %retval = zext i8 %tmp12 to i32
+        ret i32 %retval
+}
 define i32 @c(i32 %d) nounwind  {
         %e = add i32 %d, 1
         %retval = and i32 %e, 65535
         ret i32 %retval
 }
+define i64 @d(i64 %d) nounwind  {
+        %e = add i64 %d, 1
+        %retval = and i64 %e, 255
+        ret i64 %retval
+}
 define i64 @e(i64 %d) nounwind  {
         %e = add i64 %d, 1
         %retval = and i64 %e, 65535
diff --git a/test/CodeGen/X86/zext-inreg-2.ll b/test/CodeGen/X86/zext-inreg-2.ll
deleted file mode 100644
index 1209dac7f6..0000000000
--- a/test/CodeGen/X86/zext-inreg-2.ll
+++ /dev/null
@@ -1,28 +0,0 @@
-; RUN: llvm-as < %s | llc -march=x86-64 > %t
-; RUN: not grep and %t
-; RUN: not grep movzbq %t
-; RUN: not grep movzwq %t
-; RUN: not grep movzlq %t
-
-; These should use movzbl instead of 'and 255'.
-; This related to not having a ZERO_EXTEND_REG opcode.
-
-; This test was split out of zext-inreg-0.ll because these
-; cases don't yet work on x86-32 due to the 8-bit subreg
-; issue.
-
-define i32 @a(i32 %d) nounwind  {
-        %e = add i32 %d, 1
-        %retval = and i32 %e, 255
-        ret i32 %retval
-}
-define i32 @b(float %d) nounwind  {
-        %tmp12 = fptoui float %d to i8
-        %retval = zext i8 %tmp12 to i32
-        ret i32 %retval
-}
-define i64 @d(i64 %d) nounwind  {
-        %e = add i64 %d, 1
-        %retval = and i64 %e, 255
-        ret i64 %retval
-}