diff mbox series

[v2] Hexagon (target/hexagon) Fix predicated assignment to .tmp and .cur

Message ID 20221018172446.25766-1-tsimpson@quicinc.com (mailing list archive)
State New, archived
Headers show
Series [v2] Hexagon (target/hexagon) Fix predicated assignment to .tmp and .cur | expand

Commit Message

Taylor Simpson Oct. 18, 2022, 5:24 p.m. UTC
*** Changes in v2 ***
Update test case to use both true and false predicates
Add fix for .cur

Here are example instructions with a predicated .tmp/.cur assignment
    if (p1) v12.tmp = vmem(r7 + #0)
    if (p0) v12.cur = vmem(r9 + #0)
The .tmp/.cur indicates that references to v12 in the same packet
take the result of the load.  However, when the predicate is false,
the value at the start of the packet should be used.  After the packet
commits, the .tmp value is dropped, but the .cur value is maintained.

To fix this bug, we preload the original value from the HVX register
into the temporary used for the result.

Test cases added to tests/tcg/hexagon/hvx_misc.c

Co-authored-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Signed-off-by: Matheus Tavares Bernardino <quic_mathbern@quicinc.com>
Signed-off-by: Taylor Simpson <tsimpson@quicinc.com>
---
 target/hexagon/translate.h      | 12 +++++-
 tests/tcg/hexagon/hvx_misc.c    | 72 +++++++++++++++++++++++++++++++++
 target/hexagon/gen_tcg_funcs.py | 16 ++++++++
 3 files changed, 99 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/target/hexagon/translate.h b/target/hexagon/translate.h
index a245172827..2d563cea14 100644
--- a/target/hexagon/translate.h
+++ b/target/hexagon/translate.h
@@ -1,5 +1,5 @@ 
 /*
- *  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *  Copyright(c) 2019-2022 Qualcomm Innovation Center, Inc. All Rights Reserved.
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -83,6 +83,16 @@  static inline bool is_preloaded(DisasContext *ctx, int num)
     return test_bit(num, ctx->regs_written);
 }
 
+static inline bool is_tmp_vreg_preloaded(DisasContext *ctx, int num)
+{
+    return test_bit(num, ctx->vregs_updated_tmp);
+}
+
+static inline bool is_future_vreg_preloaded(DisasContext *ctx, int num)
+{
+    return test_bit(num, ctx->vregs_select);
+}
+
 intptr_t ctx_future_vreg_off(DisasContext *ctx, int regnum,
                              int num, bool alloc_ok);
 intptr_t ctx_tmp_vreg_off(DisasContext *ctx, int regnum,
diff --git a/tests/tcg/hexagon/hvx_misc.c b/tests/tcg/hexagon/hvx_misc.c
index 6e2c9ab3cd..53d5c9b44f 100644
--- a/tests/tcg/hexagon/hvx_misc.c
+++ b/tests/tcg/hexagon/hvx_misc.c
@@ -541,6 +541,75 @@  static void test_vshuff(void)
     check_output_b(__LINE__, 1);
 }
 
+static void test_load_tmp_predicated(void)
+{
+    void *p0 = buffer0;
+    void *p1 = buffer1;
+    void *pout = output;
+    bool pred = true;
+
+    for (int i = 0; i < BUFSIZE; i++) {
+        /*
+         * Load into v12 as .tmp with a predicate
+         * When the predicate is true, we get the vector from buffer1[i]
+         * When the predicate is false, we get a vector of all 1's
+         * Regardless of the predicate, the next packet should have
+         * a vector of all 1's
+         */
+        asm("v3 = vmem(%0 + #0)\n\t"
+            "r1 = #1\n\t"
+            "v12 = vsplat(r1)\n\t"
+            "p1 = !cmp.eq(%3, #0)\n\t"
+            "{\n\t"
+            "    if (p1) v12.tmp = vmem(%1 + #0)\n\t"
+            "    v4.w = vadd(v12.w, v3.w)\n\t"
+            "}\n\t"
+            "v4.w = vadd(v4.w, v12.w)\n\t"
+            "vmem(%2 + #0) = v4\n\t"
+            : : "r"(p0), "r"(p1), "r"(pout), "r"(pred)
+            : "r1", "p1", "v12", "v3", "v4", "v6", "memory");
+        p0 += sizeof(MMVector);
+        p1 += sizeof(MMVector);
+        pout += sizeof(MMVector);
+
+        for (int j = 0; j < MAX_VEC_SIZE_BYTES / 4; j++) {
+            expect[i].w[j] =
+                pred ? buffer0[i].w[j] + buffer1[i].w[j] + 1
+                     : buffer0[i].w[j] + 2;
+        }
+        pred = !pred;
+    }
+
+    check_output_w(__LINE__, BUFSIZE);
+}
+
+static void test_load_cur_predicated(void)
+{
+    bool pred = true;
+    for (int i = 0; i < BUFSIZE; i++) {
+        asm volatile("p0 = !cmp.eq(%3, #0)\n\t"
+                     "v3 = vmem(%0+#0)\n\t"
+                     /*
+                      * Preload v4 to make sure that the assignment from the
+                      * packet below is not being ignored when pred is false.
+                      */
+                     "r0 = #0x01237654\n\t"
+                     "v4 = vsplat(r0)\n\t"
+                     "{\n\t"
+                     "    if (p0) v3.cur = vmem(%1+#0)\n\t"
+                     "    v4 = v3\n\t"
+                     "}\n\t"
+                     "vmem(%2+#0) = v4\n\t"
+                     :
+                     : "r"(&buffer0[i]), "r"(&buffer1[i]),
+                       "r"(&output[i]), "r"(pred)
+                     : "r0", "p0", "v3", "v4", "memory");
+        expect[i] = pred ? buffer1[i] : buffer0[i];
+        pred = !pred;
+    }
+    check_output_w(__LINE__, BUFSIZE);
+}
+
 int main()
 {
     init_buffers();
@@ -578,6 +647,9 @@  int main()
 
     test_vshuff();
 
+    test_load_tmp_predicated();
+    test_load_cur_predicated();
+
     puts(err ? "FAIL" : "PASS");
     return err ? 1 : 0;
 }
diff --git a/target/hexagon/gen_tcg_funcs.py b/target/hexagon/gen_tcg_funcs.py
index 6dea02b0b9..de0e06ab71 100755
--- a/target/hexagon/gen_tcg_funcs.py
+++ b/target/hexagon/gen_tcg_funcs.py
@@ -173,6 +173,22 @@  def genptr_decl(f, tag, regtype, regid, regno):
                 f.write("        ctx_future_vreg_off(ctx, %s%sN," % \
                     (regtype, regid))
                 f.write(" 1, true);\n");
+            if regid != "y" and 'A_CONDEXEC' in hex_common.attribdict[tag]:
+                if hex_common.is_tmp_result(tag):
+                    preload_test_fn = "is_tmp_vreg_preloaded"
+                else:
+                    preload_test_fn = "is_future_vreg_preloaded"
+                f.write("    if (!%s(ctx, %s)) {\n" % (preload_test_fn, regN))
+                f.write("        intptr_t src_off =")
+                f.write(" offsetof(CPUHexagonState, VRegs[%s%sN]);\n"% \
+                                     (regtype, regid))
+                f.write("        tcg_gen_gvec_mov(MO_64, %s%sV_off,\n" % \
+                                     (regtype, regid))
+                f.write("                         src_off,\n")
+                f.write("                         sizeof(MMVector),\n")
+                f.write("                         sizeof(MMVector));\n")
+                f.write("    }\n")
+
             if (not hex_common.skip_qemu_helper(tag)):
                 f.write("    TCGv_ptr %s%sV = tcg_temp_new_ptr();\n" % \
                     (regtype, regid))