[AMDGPU][True16][CodeGen] Undo sub(x,c) to add in true16 flow

[broxigarchen]

Undo sub x, c -> add x, -c canonicalization in true16 fow.

This duplicating the pattern from fake16 and implemement the same pattern in true16 format

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Brox Chen (broxigarchen)

Changes

Undo sub x, c -> add x, -c canonicalization in true16 fow.

This duplicating the pattern from fake16 and implemement the same pattern in true16 format

---

Full diff: https://github.com/llvm/llvm-project/pull/118854.diff

1 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/VOP3Instructions.td (+5-1)

diff --git a/llvm/lib/Target/AMDGPU/VOP3Instructions.td b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
index 47b60bb0fdab30..ccf6ccf6e5d44a 100644
--- a/llvm/lib/Target/AMDGPU/VOP3Instructions.td
+++ b/llvm/lib/Target/AMDGPU/VOP3Instructions.td
@@ -1271,7 +1271,11 @@ let True16Predicate = NotHasTrue16BitInsts, SubtargetPredicate = isGFX10Plus in
 let True16Predicate = UseRealTrue16Insts in {
   def : OpSelBinOpClampPat<uaddsat, V_ADD_NC_U16_t16_e64>;
   def : OpSelBinOpClampPat<usubsat, V_SUB_NC_U16_t16_e64>;
-} // End OtherPredicates = [UseRealTrue16Insts]
+  def : GCNPat<
+    (add i16:$src0, (i16 NegSubInlineIntConst16:$src1)),
+    (V_SUB_NC_U16_t16_e64 0, VSrc_b16:$src0, 0, NegSubInlineIntConst16:$src1, 0, 0)
+  >;
+} // End True16Predicate = UseRealTrue16Insts
 
 let True16Predicate = UseFakeTrue16Insts in {
    def : OpSelBinOpClampPat<uaddsat, V_ADD_NC_U16_fake16_e64>;

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-x86_64-expensive-checks-debian running on gribozavr4 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/11978

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: tools/llvm-gsymutil/ARM_AArch64/macho-merged-funcs-dwarf.yaml' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
Input file: /b/1/llvm-clang-x86_64-expensive-checks-debian/build/test/tools/llvm-gsymutil/ARM_AArch64/Output/macho-merged-funcs-dwarf.yaml.tmp.dSYM
Output file (aarch64): /b/1/llvm-clang-x86_64-expensive-checks-debian/build/test/tools/llvm-gsymutil/ARM_AArch64/Output/macho-merged-funcs-dwarf.yaml.tmp.default.gSYM
Loaded 3 functions from DWARF.
Loaded 3 functions from symbol table.
warning: same address range contains different debug info. Removing:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000001
addr=0x0000000000000248, file=  1, line=  5
addr=0x0000000000000254, file=  1, line=  7
addr=0x0000000000000258, file=  1, line=  9
addr=0x000000000000025c, file=  1, line=  8
addr=0x0000000000000260, file=  1, line= 11
addr=0x0000000000000264, file=  1, line= 10
addr=0x0000000000000268, file=  1, line=  6


In favor of this one:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000047
addr=0x0000000000000248, file=  3, line=  5
addr=0x0000000000000254, file=  3, line=  7
addr=0x0000000000000258, file=  3, line=  9
addr=0x000000000000025c, file=  3, line=  8
addr=0x0000000000000260, file=  3, line= 11
addr=0x0000000000000264, file=  3, line= 10
addr=0x0000000000000268, file=  3, line=  6


warning: same address range contains different debug info. Removing:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000047
addr=0x0000000000000248, file=  3, line=  5
addr=0x0000000000000254, file=  3, line=  7
addr=0x0000000000000258, file=  3, line=  9
addr=0x000000000000025c, file=  3, line=  8
addr=0x0000000000000260, file=  3, line= 11
addr=0x0000000000000264, file=  3, line= 10
addr=0x0000000000000268, file=  3, line=  6


In favor of this one:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000030
addr=0x0000000000000248, file=  2, line=  5
addr=0x0000000000000254, file=  2, line=  7
addr=0x0000000000000258, file=  2, line=  9
addr=0x000000000000025c, file=  2, line=  8
addr=0x0000000000000260, file=  2, line= 11
addr=0x0000000000000264, file=  2, line= 10
...