Add x86 isel patterns to match what would be a ZERO_EXTEND_INREG operation,

which is represented in codegen as an 'and' operation. This matches them
with movz instructions, instead of leaving them to be matched by and
instructions with an immediate field.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54147 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 98 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index dbb12947f2..73edcb8d49 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -377,6 +377,8 @@ namespace ISD {
     // extending the low 8 bits of a 32-bit register to fill the top 24 bits
     // with the 7th bit).  The size of the smaller type is indicated by the 1th
     // operand, a ValueType node.
+    // Note that there is intentionally no corresponding ZERO_EXTEND_INREG; an
+    // AND with an appropriate constant is used instead.
     SIGN_EXTEND_INREG,
 
     /// FP_TO_[US]INT - Convert a floating point value to a signed or unsigned
diff --git a/lib/Target/X86/X86Instr64bit.td b/lib/Target/X86/X86Instr64bit.td
index 23a403068b..932e1b7afc 100644
--- a/lib/Target/X86/X86Instr64bit.td
+++ b/lib/Target/X86/X86Instr64bit.td
@@ -1240,6 +1240,12 @@ def : Pat<(and GR64:$src, i64immFFFFFFFF),
           (SUBREG_TO_REG (i64 0), 
             (i32 (EXTRACT_SUBREG GR64:$src, x86_subreg_32bit)),
             x86_subreg_32bit)>;
+// r & (2^16-1) ==> movz
+def : Pat<(and GR64:$src, 0xffff),
+          (MOVZX64rr16 (i16 (EXTRACT_SUBREG GR64:$src, x86_subreg_16bit)))>;
+// r & (2^8-1) ==> movz
+def : Pat<(and GR64:$src, 0xff),
+          (MOVZX64rr8 (i8 (EXTRACT_SUBREG GR64:$src, x86_subreg_8bit)))>;
 
 // (shl x, 1) ==> (add x, x)
 def : Pat<(shl GR64:$src1, (i8 1)), (ADD64rr GR64:$src1, GR64:$src1)>;
diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 4f3a3af0f9..9996195407 100644
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -2763,6 +2763,16 @@ def : Pat<(i32 (and (loadi32 addr:$src), (i32 65535))),(MOVZX32rm16 addr:$src)>;
 // Some peepholes
 //===----------------------------------------------------------------------===//
 
+// 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:$src1, 0xff),
+           (MOVZX32rr8 (i8 (EXTRACT_SUBREG GR32:$src1, x86_subreg_8bit)))>;
+// r & (2^8-1) ==> movz
+def : Pat<(and GR16:$src1, 0xff),
+           (MOVZX16rr8 (i8 (EXTRACT_SUBREG GR16:$src1, x86_subreg_8bit)))>;
+
 // (shl x, 1) ==> (add x, x)
 def : Pat<(shl GR8 :$src1, (i8 1)), (ADD8rr  GR8 :$src1, GR8 :$src1)>;
 def : Pat<(shl GR16:$src1, (i8 1)), (ADD16rr GR16:$src1, GR16:$src1)>;
diff --git a/test/CodeGen/X86/zext-inreg-0.ll b/test/CodeGen/X86/zext-inreg-0.ll
new file mode 100644
index 0000000000..a4ffd67f38
--- /dev/null
+++ b/test/CodeGen/X86/zext-inreg-0.ll
@@ -0,0 +1,62 @@
+; RUN: llvm-as < %s | llc -march=x86 | not grep and
+; RUN: llvm-as < %s | llc -march=x86-64 | not grep and
+
+; 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
+        ret i64 %retval
+}
+define i64 @f(i64 %d) nounwind  {
+        %e = add i64 %d, 1
+        %retval = and i64 %e, 4294967295
+        ret i64 %retval
+}
+
+define i32 @g(i8 %d) nounwind  {
+        %e = add i8 %d, 1
+        %retval = zext i8 %e to i32
+        ret i32 %retval
+}
+define i32 @h(i16 %d) nounwind  {
+        %e = add i16 %d, 1
+        %retval = zext i16 %e to i32
+        ret i32 %retval
+}
+define i64 @i(i8 %d) nounwind  {
+        %e = add i8 %d, 1
+        %retval = zext i8 %e to i64
+        ret i64 %retval
+}
+define i64 @j(i16 %d) nounwind  {
+        %e = add i16 %d, 1
+        %retval = zext i16 %e to i64
+        ret i64 %retval
+}
+define i64 @k(i32 %d) nounwind  {
+        %e = add i32 %d, 1
+        %retval = zext i32 %e to i64
+        ret i64 %retval
+}
diff --git a/test/CodeGen/X86/zext-inreg-1.ll b/test/CodeGen/X86/zext-inreg-1.ll
new file mode 100644
index 0000000000..4a80fe5fe3
--- /dev/null
+++ b/test/CodeGen/X86/zext-inreg-1.ll
@@ -0,0 +1,18 @@
+; RUN: llvm-as < %s | llc -march=x86 | not grep and
+
+; These tests differ from the ones in zext-inreg-0.ll in that
+; on x86-64 they do require and instructions.
+
+; These should use movzbl instead of 'and 255'.
+; This related to not having ZERO_EXTEND_REG node.
+
+define i64 @g(i64 %d) nounwind  {
+        %e = add i64 %d, 1
+        %retval = and i64 %e, 1099511627775
+        ret i64 %retval
+}
+define i64 @h(i64 %d) nounwind  {
+        %e = add i64 %d, 1
+        %retval = and i64 %e, 281474976710655
+        ret i64 %retval
+}