[llvm-branch-commits] [SPARC] Promote i32 CTTZ when we have VIS3 (PR #135894)

via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Tue Apr 15 18:29:18 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-sparc

Author: Koakuma (koachan)

<details>
<summary>Changes</summary>

CTTZ can be implemented in terms of CTLZ, for which there's a native
instruction in VIS3.
Promote i32 CTTZ in that case so that the native instruction gets used.


---
Full diff: https://github.com/llvm/llvm-project/pull/135894.diff


2 Files Affected:

- (modified) llvm/lib/Target/Sparc/SparcISelLowering.cpp (+4-1) 
- (modified) llvm/test/CodeGen/SPARC/cttz.ll (+188-63) 


``````````diff
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index c7dd96757ebb5..bbc15c3ebf4dc 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -1820,7 +1820,8 @@ SparcTargetLowering::SparcTargetLowering(const TargetMachine &TM,
   setOperationAction(ISD::FSINCOS, MVT::f32, Expand);
   setOperationAction(ISD::FREM , MVT::f32, Expand);
   setOperationAction(ISD::FMA  , MVT::f32, Expand);
-  setOperationAction(ISD::CTTZ , MVT::i32, Expand);
+  setOperationAction(ISD::CTTZ, MVT::i32,
+                     Subtarget->isVIS3() ? Promote : Expand);
   setOperationAction(ISD::CTLZ, MVT::i32,
                      Subtarget->isVIS3() ? Promote : Expand);
   setOperationAction(ISD::ROTL , MVT::i32, Expand);
@@ -1998,6 +1999,8 @@ SparcTargetLowering::SparcTargetLowering(const TargetMachine &TM,
   if (Subtarget->isVIS3()) {
     setOperationAction(ISD::CTLZ_ZERO_UNDEF, MVT::i32, Promote);
     setOperationAction(ISD::CTLZ_ZERO_UNDEF, MVT::i64, Legal);
+    setOperationAction(ISD::CTTZ_ZERO_UNDEF, MVT::i32, Promote);
+    setOperationAction(ISD::CTTZ_ZERO_UNDEF, MVT::i64, Expand);
   }
 
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
diff --git a/llvm/test/CodeGen/SPARC/cttz.ll b/llvm/test/CodeGen/SPARC/cttz.ll
index eab2433a074a2..bc3fa13c105b7 100644
--- a/llvm/test/CodeGen/SPARC/cttz.ll
+++ b/llvm/test/CodeGen/SPARC/cttz.ll
@@ -1,70 +1,195 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=sparc -mcpu=v9 | FileCheck %s
+; RUN: llc < %s -mtriple=sparcv9 | FileCheck %s -check-prefix=V9
+; RUN: llc < %s -mtriple=sparcv9 -mattr=popc | FileCheck %s -check-prefix=POPC
+; RUN: llc < %s -mtriple=sparcv9 -mattr=vis3 | FileCheck %s -check-prefix=VIS3
 
-define i32 @f(i32 %x) {
-; CHECK-LABEL: f:
-; CHECK:         .cfi_startproc
-; CHECK-NEXT:  ! %bb.0: ! %entry
-; CHECK-NEXT:    sub %g0, %o0, %o1
-; CHECK-NEXT:    and %o0, %o1, %o1
-; CHECK-NEXT:    sethi 122669, %o2
-; CHECK-NEXT:    or %o2, 305, %o2
-; CHECK-NEXT:    smul %o1, %o2, %o1
-; CHECK-NEXT:    srl %o1, 27, %o1
-; CHECK-NEXT:    sethi %hi(.LCPI0_0), %o2
-; CHECK-NEXT:    add %o2, %lo(.LCPI0_0), %o2
-; CHECK-NEXT:    ldub [%o2+%o1], %o1
-; CHECK-NEXT:    cmp %o0, 0
-; CHECK-NEXT:    move %icc, 0, %o1
-; CHECK-NEXT:    retl
-; CHECK-NEXT:    mov %o1, %o0
-entry:
-  %0 = call i32 @llvm.cttz.i32(i32 %x, i1 true)
-  %1 = icmp eq i32 %x, 0
-  %2 = select i1 %1, i32 0, i32 %0
-  %3 = trunc i32 %2 to i8
-  %conv = zext i8 %3 to i32
-  ret i32 %conv
+define i32 @i32_nopoison(i32 %x) nounwind {
+; V9-LABEL: i32_nopoison:
+; V9:       ! %bb.0:
+; V9-NEXT:    cmp %o0, 0
+; V9-NEXT:    be %icc, .LBB0_2
+; V9-NEXT:    nop
+; V9-NEXT:  ! %bb.1: ! %cond.false
+; V9-NEXT:    sub %g0, %o0, %o1
+; V9-NEXT:    and %o0, %o1, %o0
+; V9-NEXT:    sethi 122669, %o1
+; V9-NEXT:    or %o1, 305, %o1
+; V9-NEXT:    mulx %o0, %o1, %o0
+; V9-NEXT:    srl %o0, 27, %o0
+; V9-NEXT:    srl %o0, 0, %o0
+; V9-NEXT:    sethi %h44(.LCPI0_0), %o1
+; V9-NEXT:    add %o1, %m44(.LCPI0_0), %o1
+; V9-NEXT:    sllx %o1, 12, %o1
+; V9-NEXT:    add %o1, %l44(.LCPI0_0), %o1
+; V9-NEXT:    retl
+; V9-NEXT:    ldub [%o1+%o0], %o0
+; V9-NEXT:  .LBB0_2:
+; V9-NEXT:    retl
+; V9-NEXT:    mov 32, %o0
+;
+; POPC-LABEL: i32_nopoison:
+; POPC:       ! %bb.0:
+; POPC-NEXT:    cmp %o0, 0
+; POPC-NEXT:    be %icc, .LBB0_2
+; POPC-NEXT:    nop
+; POPC-NEXT:  ! %bb.1: ! %cond.false
+; POPC-NEXT:    add %o0, -1, %o1
+; POPC-NEXT:    andn %o1, %o0, %o0
+; POPC-NEXT:    srl %o0, 0, %o0
+; POPC-NEXT:    retl
+; POPC-NEXT:    popc %o0, %o0
+; POPC-NEXT:  .LBB0_2:
+; POPC-NEXT:    retl
+; POPC-NEXT:    mov 32, %o0
+;
+; VIS3-LABEL: i32_nopoison:
+; VIS3:       ! %bb.0:
+; VIS3-NEXT:    cmp %o0, 0
+; VIS3-NEXT:    be %icc, .LBB0_2
+; VIS3-NEXT:    nop
+; VIS3-NEXT:  ! %bb.1: ! %cond.false
+; VIS3-NEXT:    add %o0, -1, %o1
+; VIS3-NEXT:    andn %o1, %o0, %o0
+; VIS3-NEXT:    lzcnt %o0, %o0
+; VIS3-NEXT:    mov 64, %o1
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    sub %o1, %o0, %o0
+; VIS3-NEXT:  .LBB0_2:
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    mov 32, %o0
+  %ret = call i32 @llvm.cttz.i32(i32 %x, i1 false)
+  ret i32 %ret
 }
 
-define i64 @g(i64 %x) {
-; CHECK-LABEL: g:
-; CHECK:         .cfi_startproc
-; CHECK-NEXT:  ! %bb.0: ! %entry
-; CHECK-NEXT:    sub %g0, %o1, %o2
-; CHECK-NEXT:    and %o1, %o2, %o2
-; CHECK-NEXT:    sethi 122669, %o3
-; CHECK-NEXT:    or %o3, 305, %o3
-; CHECK-NEXT:    smul %o2, %o3, %o2
-; CHECK-NEXT:    sethi %hi(.LCPI1_0), %o4
-; CHECK-NEXT:    add %o4, %lo(.LCPI1_0), %o4
-; CHECK-NEXT:    sub %g0, %o0, %o5
-; CHECK-NEXT:    and %o0, %o5, %o5
-; CHECK-NEXT:    smul %o5, %o3, %o3
-; CHECK-NEXT:    srl %o3, 27, %o3
-; CHECK-NEXT:    ldub [%o4+%o3], %o3
-; CHECK-NEXT:    srl %o2, 27, %o2
-; CHECK-NEXT:    ldub [%o4+%o2], %o4
-; CHECK-NEXT:    add %o3, 32, %o2
-; CHECK-NEXT:    cmp %o1, 0
-; CHECK-NEXT:    movne %icc, %o4, %o2
-; CHECK-NEXT:    or %o1, %o0, %o0
-; CHECK-NEXT:    cmp %o0, 0
-; CHECK-NEXT:    move %icc, 0, %o2
-; CHECK-NEXT:    mov %g0, %o0
-; CHECK-NEXT:    retl
-; CHECK-NEXT:    mov %o2, %o1
-entry:
-  %0 = call i64 @llvm.cttz.i64(i64 %x, i1 true)
-  %1 = icmp eq i64 %x, 0
-  %2 = select i1 %1, i64 0, i64 %0
-  %3 = trunc i64 %2 to i32
-  %conv = zext i32 %3 to i64
-  ret i64 %conv
+define i32 @i32_poison(i32 %x) nounwind {
+; V9-LABEL: i32_poison:
+; V9:       ! %bb.0:
+; V9-NEXT:    sub %g0, %o0, %o1
+; V9-NEXT:    and %o0, %o1, %o0
+; V9-NEXT:    sethi 122669, %o1
+; V9-NEXT:    or %o1, 305, %o1
+; V9-NEXT:    mulx %o0, %o1, %o0
+; V9-NEXT:    srl %o0, 27, %o0
+; V9-NEXT:    srl %o0, 0, %o0
+; V9-NEXT:    sethi %h44(.LCPI1_0), %o1
+; V9-NEXT:    add %o1, %m44(.LCPI1_0), %o1
+; V9-NEXT:    sllx %o1, 12, %o1
+; V9-NEXT:    add %o1, %l44(.LCPI1_0), %o1
+; V9-NEXT:    retl
+; V9-NEXT:    ldub [%o1+%o0], %o0
+;
+; POPC-LABEL: i32_poison:
+; POPC:       ! %bb.0:
+; POPC-NEXT:    add %o0, -1, %o1
+; POPC-NEXT:    andn %o1, %o0, %o0
+; POPC-NEXT:    srl %o0, 0, %o0
+; POPC-NEXT:    retl
+; POPC-NEXT:    popc %o0, %o0
+;
+; VIS3-LABEL: i32_poison:
+; VIS3:       ! %bb.0:
+; VIS3-NEXT:    add %o0, -1, %o1
+; VIS3-NEXT:    andn %o1, %o0, %o0
+; VIS3-NEXT:    lzcnt %o0, %o0
+; VIS3-NEXT:    mov 64, %o1
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    sub %o1, %o0, %o0
+  %ret = call i32 @llvm.cttz.i32(i32 %x, i1 true)
+  ret i32 %ret
 }
 
-; Function Attrs: nocallback nofree nosync nounwind readnone speculatable willreturn
-declare i32 @llvm.cttz.i32(i32, i1 immarg) #0
-declare i64 @llvm.cttz.i64(i64, i1 immarg) #0
+define i64 @i64_nopoison(i64 %x) nounwind {
+; V9-LABEL: i64_nopoison:
+; V9:       ! %bb.0:
+; V9-NEXT:    brz %o0, .LBB2_2
+; V9-NEXT:    nop
+; V9-NEXT:  ! %bb.1: ! %cond.false
+; V9-NEXT:    sub %g0, %o0, %o1
+; V9-NEXT:    and %o0, %o1, %o0
+; V9-NEXT:    sethi 3362647, %o1
+; V9-NEXT:    or %o1, 447, %o1
+; V9-NEXT:    sethi 34344, %o2
+; V9-NEXT:    or %o2, 914, %o2
+; V9-NEXT:    sllx %o2, 32, %o2
+; V9-NEXT:    or %o2, %o1, %o1
+; V9-NEXT:    mulx %o0, %o1, %o0
+; V9-NEXT:    srlx %o0, 58, %o0
+; V9-NEXT:    sethi %h44(.LCPI2_0), %o1
+; V9-NEXT:    add %o1, %m44(.LCPI2_0), %o1
+; V9-NEXT:    sllx %o1, 12, %o1
+; V9-NEXT:    add %o1, %l44(.LCPI2_0), %o1
+; V9-NEXT:    retl
+; V9-NEXT:    ldub [%o1+%o0], %o0
+; V9-NEXT:  .LBB2_2:
+; V9-NEXT:    retl
+; V9-NEXT:    mov 64, %o0
+;
+; POPC-LABEL: i64_nopoison:
+; POPC:       ! %bb.0:
+; POPC-NEXT:    brz %o0, .LBB2_2
+; POPC-NEXT:    nop
+; POPC-NEXT:  ! %bb.1: ! %cond.false
+; POPC-NEXT:    add %o0, -1, %o1
+; POPC-NEXT:    andn %o1, %o0, %o0
+; POPC-NEXT:    retl
+; POPC-NEXT:    popc %o0, %o0
+; POPC-NEXT:  .LBB2_2:
+; POPC-NEXT:    retl
+; POPC-NEXT:    mov 64, %o0
+;
+; VIS3-LABEL: i64_nopoison:
+; VIS3:       ! %bb.0:
+; VIS3-NEXT:    brz %o0, .LBB2_2
+; VIS3-NEXT:    nop
+; VIS3-NEXT:  ! %bb.1: ! %cond.false
+; VIS3-NEXT:    add %o0, -1, %o1
+; VIS3-NEXT:    andn %o1, %o0, %o0
+; VIS3-NEXT:    lzcnt %o0, %o0
+; VIS3-NEXT:    mov 64, %o1
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    sub %o1, %o0, %o0
+; VIS3-NEXT:  .LBB2_2:
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    mov 64, %o0
+  %ret = call i64 @llvm.cttz.i64(i64 %x, i1 false)
+  ret i64 %ret
+}
 
-attributes #0 = { nocallback nofree nosync nounwind readnone speculatable willreturn }
+define i64 @i64_poison(i64 %x) nounwind {
+; V9-LABEL: i64_poison:
+; V9:       ! %bb.0:
+; V9-NEXT:    sub %g0, %o0, %o1
+; V9-NEXT:    and %o0, %o1, %o0
+; V9-NEXT:    sethi 3362647, %o1
+; V9-NEXT:    or %o1, 447, %o1
+; V9-NEXT:    sethi 34344, %o2
+; V9-NEXT:    or %o2, 914, %o2
+; V9-NEXT:    sllx %o2, 32, %o2
+; V9-NEXT:    or %o2, %o1, %o1
+; V9-NEXT:    mulx %o0, %o1, %o0
+; V9-NEXT:    srlx %o0, 58, %o0
+; V9-NEXT:    sethi %h44(.LCPI3_0), %o1
+; V9-NEXT:    add %o1, %m44(.LCPI3_0), %o1
+; V9-NEXT:    sllx %o1, 12, %o1
+; V9-NEXT:    add %o1, %l44(.LCPI3_0), %o1
+; V9-NEXT:    retl
+; V9-NEXT:    ldub [%o1+%o0], %o0
+;
+; POPC-LABEL: i64_poison:
+; POPC:       ! %bb.0:
+; POPC-NEXT:    add %o0, -1, %o1
+; POPC-NEXT:    andn %o1, %o0, %o0
+; POPC-NEXT:    retl
+; POPC-NEXT:    popc %o0, %o0
+;
+; VIS3-LABEL: i64_poison:
+; VIS3:       ! %bb.0:
+; VIS3-NEXT:    add %o0, -1, %o1
+; VIS3-NEXT:    andn %o1, %o0, %o0
+; VIS3-NEXT:    lzcnt %o0, %o0
+; VIS3-NEXT:    mov 64, %o1
+; VIS3-NEXT:    retl
+; VIS3-NEXT:    sub %o1, %o0, %o0
+  %ret = call i64 @llvm.cttz.i64(i64 %x, i1 true)
+  ret i64 %ret
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/135894


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