tcg: Add field extraction primitives

Adds tcg_gen_extract_* and tcg_gen_sextract_* for extraction of fixed position bitfields, much like we already have for deposit. Reviewed-by: Alex Bennée <[email protected]> Signed-off-by: Richard Henderson <[email protected]>
stefanha · Jan 10, 2017 · 7ec8bab · 7ec8bab
1 parent 41a0e54
commit 7ec8bab
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Showing 15 changed files with 426 additions and 2 deletions.
diff --git a/tcg/README b/tcg/README
@@ -314,11 +314,27 @@ The bitfield is described by POS/LEN, which are immediate values:
   LEN - the length of the bitfield
   POS - the position of the first bit, counting from the LSB
 
-For example, pos=8, len=4 indicates a 4-bit field at bit 8.
-This operation would be equivalent to
+For example, "deposit_i32 dest, t1, t2, 8, 4" indicates a 4-bit field
+at bit 8.  This operation would be equivalent to
 
   dest = (t1 & ~0x0f00) | ((t2 << 8) & 0x0f00)
 
+* extract_i32/i64 dest, t1, pos, len
+* sextract_i32/i64 dest, t1, pos, len
+
+Extract a bitfield from T1, placing the result in DEST.
+The bitfield is described by POS/LEN, which are immediate values,
+as above for deposit.  For extract_*, the result will be extended
+to the left with zeros; for sextract_*, the result will be extended
+to the left with copies of the bitfield sign bit at pos + len - 1.
+
+For example, "sextract_i32 dest, t1, 8, 4" indicates a 4-bit field
+at bit 8.  This operation would be equivalent to
+
+  dest = (t1 << 20) >> 28
+
+(using an arithmetic right shift).
+
 * extrl_i64_i32 t0, t1
 
 For 64-bit hosts only, extract the low 32-bits of input T1 and place it

diff --git a/tcg/aarch64/tcg-target.h b/tcg/aarch64/tcg-target.h
@@ -63,6 +63,8 @@ typedef enum {
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
 #define TCG_TARGET_HAS_deposit_i32      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_add2_i32         1
 #define TCG_TARGET_HAS_sub2_i32         1
@@ -93,6 +95,8 @@ typedef enum {
 #define TCG_TARGET_HAS_nand_i64         0
 #define TCG_TARGET_HAS_nor_i64          0
 #define TCG_TARGET_HAS_deposit_i64      1
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1

diff --git a/tcg/arm/tcg-target.h b/tcg/arm/tcg-target.h
@@ -80,6 +80,8 @@ extern bool use_idiv_instructions;
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
 #define TCG_TARGET_HAS_deposit_i32      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_mulu2_i32        1
 #define TCG_TARGET_HAS_muls2_i32        1

diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h
@@ -94,6 +94,8 @@ extern bool have_bmi1;
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
 #define TCG_TARGET_HAS_deposit_i32      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_add2_i32         1
 #define TCG_TARGET_HAS_sub2_i32         1
@@ -124,6 +126,8 @@ extern bool have_bmi1;
 #define TCG_TARGET_HAS_nand_i64         0
 #define TCG_TARGET_HAS_nor_i64          0
 #define TCG_TARGET_HAS_deposit_i64      1
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1

diff --git a/tcg/ia64/tcg-target.h b/tcg/ia64/tcg-target.h
@@ -149,6 +149,10 @@ typedef enum {
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_deposit_i32      1
 #define TCG_TARGET_HAS_deposit_i64      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i32     0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_add2_i32         0
 #define TCG_TARGET_HAS_add2_i64         0
 #define TCG_TARGET_HAS_sub2_i32         0

diff --git a/tcg/mips/tcg-target.h b/tcg/mips/tcg-target.h
@@ -158,6 +158,8 @@ extern bool use_mips32r2_instructions;
 #define TCG_TARGET_HAS_movcond_i32      use_movnz_instructions
 #define TCG_TARGET_HAS_bswap16_i32      use_mips32r2_instructions
 #define TCG_TARGET_HAS_deposit_i32      use_mips32r2_instructions
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_ext8s_i32        use_mips32r2_instructions
 #define TCG_TARGET_HAS_ext16s_i32       use_mips32r2_instructions
 #define TCG_TARGET_HAS_rot_i32          use_mips32r2_instructions

diff --git a/tcg/optimize.c b/tcg/optimize.c
@@ -878,6 +878,19 @@ void tcg_optimize(TCGContext *s)
                              temps[args[2]].mask);
             break;
 
+        CASE_OP_32_64(extract):
+            mask = extract64(temps[args[1]].mask, args[2], args[3]);
+            if (args[2] == 0) {
+                affected = temps[args[1]].mask & ~mask;
+            }
+            break;
+        CASE_OP_32_64(sextract):
+            mask = sextract64(temps[args[1]].mask, args[2], args[3]);
+            if (args[2] == 0 && (tcg_target_long)mask >= 0) {
+                affected = temps[args[1]].mask & ~mask;
+            }
+            break;
+
         CASE_OP_32_64(or):
         CASE_OP_32_64(xor):
             mask = temps[args[1]].mask | temps[args[2]].mask;
@@ -1048,6 +1061,22 @@ void tcg_optimize(TCGContext *s)
             }
             goto do_default;
 
+        CASE_OP_32_64(extract):
+            if (temp_is_const(args[1])) {
+                tmp = extract64(temps[args[1]].val, args[2], args[3]);
+                tcg_opt_gen_movi(s, op, args, args[0], tmp);
+                break;
+            }
+            goto do_default;
+
+        CASE_OP_32_64(sextract):
+            if (temp_is_const(args[1])) {
+                tmp = sextract64(temps[args[1]].val, args[2], args[3]);
+                tcg_opt_gen_movi(s, op, args, args[0], tmp);
+                break;
+            }
+            goto do_default;
+
         CASE_OP_32_64(setcond):
             tmp = do_constant_folding_cond(opc, args[1], args[2], args[3]);
             if (tmp != 2) {

diff --git a/tcg/ppc/tcg-target.h b/tcg/ppc/tcg-target.h
@@ -69,6 +69,8 @@ typedef enum {
 #define TCG_TARGET_HAS_nand_i32         1
 #define TCG_TARGET_HAS_nor_i32          1
 #define TCG_TARGET_HAS_deposit_i32      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_mulu2_i32        0
 #define TCG_TARGET_HAS_muls2_i32        0
@@ -100,6 +102,8 @@ typedef enum {
 #define TCG_TARGET_HAS_nand_i64         1
 #define TCG_TARGET_HAS_nor_i64          1
 #define TCG_TARGET_HAS_deposit_i64      1
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1

diff --git a/tcg/s390/tcg-target.h b/tcg/s390/tcg-target.h
@@ -66,6 +66,8 @@ typedef enum TCGReg {
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
 #define TCG_TARGET_HAS_deposit_i32      1
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_add2_i32         1
 #define TCG_TARGET_HAS_sub2_i32         1
@@ -95,6 +97,8 @@ typedef enum TCGReg {
 #define TCG_TARGET_HAS_nand_i64         0
 #define TCG_TARGET_HAS_nor_i64          0
 #define TCG_TARGET_HAS_deposit_i64      1
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1

diff --git a/tcg/sparc/tcg-target.h b/tcg/sparc/tcg-target.h
@@ -111,6 +111,8 @@ extern bool use_vis3_instructions;
 #define TCG_TARGET_HAS_nand_i32         0
 #define TCG_TARGET_HAS_nor_i32          0
 #define TCG_TARGET_HAS_deposit_i32      0
+#define TCG_TARGET_HAS_extract_i32      0
+#define TCG_TARGET_HAS_sextract_i32     0
 #define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_add2_i32         1
 #define TCG_TARGET_HAS_sub2_i32         1
@@ -141,6 +143,8 @@ extern bool use_vis3_instructions;
 #define TCG_TARGET_HAS_nand_i64         0
 #define TCG_TARGET_HAS_nor_i64          0
 #define TCG_TARGET_HAS_deposit_i64      0
+#define TCG_TARGET_HAS_extract_i64      0
+#define TCG_TARGET_HAS_sextract_i64     0
 #define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_add2_i64         1
 #define TCG_TARGET_HAS_sub2_i64         1