[GlobalIsel][X86] Legalize G_SELECT

[tschuett]

Summary

With bug fixes. The legalizer got more powerful over the last weeks.

[arsenm]

llvm/test/CodeGen/X86/GlobalISel/legalize-select.mir

27

Try tests with some other address spaces (in particular the 32-bit ones on x64)

[RKSimon]

llvm/test/CodeGen/X86/GlobalISel/legalize-leading-zeros.mir

3

Can this now be reduced to:

# RUN: llc -mtriple=i386-linux-gnu -mattr=+lzcnt -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X86

llvm/test/CodeGen/X86/GlobalISel/legalize-trailing-zeros-undef.mir

3

Can this now be reduced to:

# RUN: llc -mtriple=i386-linux-gnu -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X86

llvm/test/CodeGen/X86/GlobalISel/legalize-trailing-zeros.mir

3

Can this now be reduced to:

# RUN: llc -mtriple=i386-linux-gnu -mattr=+bmi -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X86

[tschuett]

due to arc issues superseded by https://reviews.llvm.org/D152271

llvm/lib/Target/X86/X86LegalizerInfo.cpp

getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
           (Query.Opcode == G_ANYEXT && Query.Types[0] == s128) ||
           (Is64Bit && Query.Types[0] == s64);
       })
     .widenScalarToNextPow2(0, /*Min=*/8)
     .clampScalar(0, s8, sMaxScalar)
     .widenScalarToNextPow2(1, /*Min=*/8)
     .clampScalar(1, s8, sMaxScalar);
 
+  // todo: vectors
+  getActionDefinitionsBuilder(G_SELECT)
+    .legalFor({{s8, s8}, {s16, s16}, {s32, s32}, {s64, s64}, {p0, p0}})
+    .widenScalarToNextPow2(0, /*Min=*/8)
+    .clampScalar(0, s8, sMaxScalar)
+    .widenScalarToNextPow2(1, /*Min=*/8)
+    .clampScalar(1, s8, sMaxScalar);
+
   setLegalizerInfo32bit();
   setLegalizerInfo64bit();
   setLegalizerInfoSSE1();
   setLegalizerInfoSSE2();
   setLegalizerInfoAVX();
   setLegalizerInfoAVX2();
   setLegalizerInfoAVX512();
 

llvm/test/CodeGen/X86/GlobalISel/legalize-leading-zeros.mir

 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 2
 # RUN: llc -mtriple=x86_64-linux-gnu -mattr=+lzcnt -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X64
 # RUN: llc -mtriple=i386-linux-gnu -mattr=+lzcnt -run-pass=legalizer -global-isel-abort=2 -pass-remarks-missed='gisel*'  %s 2>%t -o - | FileCheck %s --check-prefixes=CHECK,X86
-# RUN: FileCheck -check-prefix=ERR32  %s < %t
-
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %13:_(s32), %14:_(s1) = G_USUBE %8:_, %10:_, %12:_ (in function: test_ctlz35)
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %1:_(s64) = G_SELECT %6:_(s1), %9:_, %10:_ (in function: test_ctlz64)
 
 # test count leading zeros for s16, s32, and s64
 
 ---
 name:            test_ctlz35
 alignment:       16
 legalized:       false
 regBankSelected: false
bb.1:
     ; X86: [[DEF:%[0-9]+]]:_(s64) = IMPLICIT_DEF
     ; X86-NEXT: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF]](s64)
     ; X86-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
     ; X86-NEXT: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[UV1]](s32), [[C]]
     ; X86-NEXT: [[CTLZ:%[0-9]+]]:_(s64) = G_CTLZ [[UV]](s32)
     ; X86-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 32
     ; X86-NEXT: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[CTLZ]], [[C1]]
     ; X86-NEXT: [[CTLZ_ZERO_UNDEF:%[0-9]+]]:_(s64) = G_CTLZ_ZERO_UNDEF [[UV1]](s32)
-    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[ICMP]](s1), [[ADD]], [[CTLZ_ZERO_UNDEF]]
-    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[SELECT]](s64)
+    ; X86-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ADD]](s64)
+    ; X86-NEXT: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CTLZ_ZERO_UNDEF]](s64)
+    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[UV2]], [[UV4]]
+    ; X86-NEXT: [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[ICMP]](s1)
+    ; X86-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ZEXT]](s8), [[UV3]], [[UV5]]
+    ; X86-NEXT: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[SELECT]](s32), [[SELECT1]](s32)
+    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[MV]](s64)
     ; X86-NEXT: RET 0, implicit [[COPY]](s64)
     %0:_(s64) = IMPLICIT_DEF
     %1:_(s64) = G_CTLZ %0
     %2:_(s64) = COPY %1(s64)
     RET 0, implicit %2
 ...
 ---
 name:            test_ctlz32

llvm/test/CodeGen/X86/GlobalISel/legalize-select.mir

+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 2
+# RUN: llc -mtriple=i386-linux-gnu -run-pass=legalizer %s -o - | FileCheck %s --check-prefix=X86-32
+# RUN: llc -mtriple=x86_64-linux-gnu -run-pass=legalizer %s -o - | FileCheck %s --check-prefix=X86-64
+
+# test select
+
+...
+---
+name:            test_selectp0
+body:             |
+  bb.1:
+    ; X86-32-LABEL: name: test_selectp0
+    ; X86-32: [[DEF:%[0-9]+]]:_(p0) = IMPLICIT_DEF
+    ; X86-32-NEXT: [[COPY:%[0-9]+]]:_(p0) = COPY [[DEF]](p0)
+    ; X86-32-NEXT: RET 0, implicit [[COPY]](p0)
+    ; X86-64-LABEL: name: test_selectp0
+    ; X86-64: [[DEF:%[0-9]+]]:_(p0) = IMPLICIT_DEF
+    ; X86-64-NEXT: [[COPY:%[0-9]+]]:_(p0) = COPY [[DEF]](p0)
+    ; X86-64-NEXT: RET 0, implicit [[COPY]](p0)
+    %0:_(s1) = IMPLICIT_DEF
+    %1:_(p0) = IMPLICIT_DEF
+    %2:_(p0) = IMPLICIT_DEF
+    %3:_(p0) = G_SELECT %0, %1, %2
+    %4:_(p0) = COPY %1(p0)
+    RET 0, implicit %4
+
+...
+---
+name:            test_selects10
+body:             |
+  bb.1:
+    ; X86-32-LABEL: name: test_selects10
+    ; X86-32: [[DEF:%[0-9]+]]:_(s10) = IMPLICIT_DEF
+    ; X86-32-NEXT: [[COPY:%[0-9]+]]:_(s10) = COPY [[DEF]](s10)
+    ; X86-32-NEXT: RET 0, implicit [[COPY]](s10)
+    ; X86-64-LABEL: name: test_selects10
+    ; X86-64: [[DEF:%[0-9]+]]:_(s10) = IMPLICIT_DEF
+    ; X86-64-NEXT: [[COPY:%[0-9]+]]:_(s10) = COPY [[DEF]](s10)
+    ; X86-64-NEXT: RET 0, implicit [[COPY]](s10)
+    %0:_(s1) = IMPLICIT_DEF
+    %1:_(s10) = IMPLICIT_DEF
+    %2:_(s10) = IMPLICIT_DEF
+    %3:_(s10) = G_SELECT %0, %1, %2
+    %4:_(s10) = COPY %1(s10)
+    RET 0, implicit %4
+
+...
+---
+name:            test_select32
+body:             |
+  bb.1:
+    ; X86-32-LABEL: name: test_select32
+    ; X86-32: [[DEF:%[0-9]+]]:_(s32) = IMPLICIT_DEF
+    ; X86-32-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY [[DEF]](s32)
+    ; X86-32-NEXT: RET 0, implicit [[COPY]](s32)
+    ; X86-64-LABEL: name: test_select32
+    ; X86-64: [[DEF:%[0-9]+]]:_(s32) = IMPLICIT_DEF
+    ; X86-64-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY [[DEF]](s32)
+    ; X86-64-NEXT: RET 0, implicit [[COPY]](s32)
+    %0:_(s1) = IMPLICIT_DEF
+    %1:_(s32) = IMPLICIT_DEF
+    %2:_(s32) = IMPLICIT_DEF
+    %3:_(s32) = G_SELECT %0, %1, %2
+    %4:_(s32) = COPY %1(s32)
+    RET 0, implicit %4
+
+...
+---
+name:            test_select16
+body:             |
+  bb.1:
+    ; X86-32-LABEL: name: test_select16
+    ; X86-32: [[DEF:%[0-9]+]]:_(s16) = IMPLICIT_DEF
+    ; X86-32-NEXT: [[COPY:%[0-9]+]]:_(s16) = COPY [[DEF]](s16)
+    ; X86-32-NEXT: RET 0, implicit [[COPY]](s16)
+    ; X86-64-LABEL: name: test_select16
+    ; X86-64: [[DEF:%[0-9]+]]:_(s16) = IMPLICIT_DEF
+    ; X86-64-NEXT: [[COPY:%[0-9]+]]:_(s16) = COPY [[DEF]](s16)
+    ; X86-64-NEXT: RET 0, implicit [[COPY]](s16)
+    %0:_(s1) = IMPLICIT_DEF
+    %1:_(s16) = IMPLICIT_DEF
+    %2:_(s16) = IMPLICIT_DEF
+    %3:_(s16) = G_SELECT %0, %1, %2
+    %4:_(s16) = COPY %1(s16)
+    RET 0, implicit %4
+
+...

llvm/test/CodeGen/X86/GlobalISel/legalize-trailing-zeros-undef.mir

 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 2
 # RUN: llc -mtriple=x86_64-linux-gnu -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X64
 # RUN: llc -mtriple=i386-linux-gnu -run-pass=legalizer -global-isel-abort=2 -pass-remarks-missed='gisel*'  %s 2>%t -o - | FileCheck %s --check-prefixes=CHECK,X86
-# RUN: FileCheck -check-prefix=ERR32  %s < %t
-
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %4:_(s64) = G_SELECT %8:_(s1), %11:_, %12:_ (in function: test_cttz35)
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %1:_(s64) = G_SELECT %6:_(s1), %9:_, %10:_ (in function: test_cttz64)
 
 # test count leading zeros for s16, s32, and s64
 
 ---
 name:            test_cttz35
 alignment:       16
 legalized:       false
 regBankSelected: false
bb.1:
     ; X86-NEXT: [[ANYEXT:%[0-9]+]]:_(s64) = G_ANYEXT [[DEF]](s35)
     ; X86-NEXT: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ANYEXT]](s64)
     ; X86-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
     ; X86-NEXT: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[UV]](s32), [[C]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV1]](s32)
     ; X86-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 32
     ; X86-NEXT: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[CTTZ_ZERO_UNDEF]], [[C1]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF1:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV]](s32)
-    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[ICMP]](s1), [[ADD]], [[CTTZ_ZERO_UNDEF1]]
-    ; X86-NEXT: [[TRUNC:%[0-9]+]]:_(s35) = G_TRUNC [[SELECT]](s64)
+    ; X86-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ADD]](s64)
+    ; X86-NEXT: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CTTZ_ZERO_UNDEF1]](s64)
+    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[UV2]], [[UV4]]
+    ; X86-NEXT: [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[ICMP]](s1)
+    ; X86-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ZEXT]](s8), [[UV3]], [[UV5]]
+    ; X86-NEXT: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[SELECT]](s32), [[SELECT1]](s32)
+    ; X86-NEXT: [[TRUNC:%[0-9]+]]:_(s35) = G_TRUNC [[MV]](s64)
     ; X86-NEXT: [[COPY:%[0-9]+]]:_(s35) = COPY [[TRUNC]](s35)
     ; X86-NEXT: RET 0, implicit [[COPY]](s35)
     %0:_(s35) = IMPLICIT_DEF
     %1:_(s35) = G_CTTZ_ZERO_UNDEF %0
     %2:_(s35) = COPY %1(s35)
     RET 0, implicit %2
 ...
 ---
bb.1:
     ; X86: [[DEF:%[0-9]+]]:_(s64) = IMPLICIT_DEF
     ; X86-NEXT: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF]](s64)
     ; X86-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
     ; X86-NEXT: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[UV]](s32), [[C]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV1]](s32)
     ; X86-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 32
     ; X86-NEXT: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[CTTZ_ZERO_UNDEF]], [[C1]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF1:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV]](s32)
-    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[ICMP]](s1), [[ADD]], [[CTTZ_ZERO_UNDEF1]]
-    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[SELECT]](s64)
+    ; X86-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ADD]](s64)
+    ; X86-NEXT: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CTTZ_ZERO_UNDEF1]](s64)
+    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[UV2]], [[UV4]]
+    ; X86-NEXT: [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[ICMP]](s1)
+    ; X86-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ZEXT]](s8), [[UV3]], [[UV5]]
+    ; X86-NEXT: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[SELECT]](s32), [[SELECT1]](s32)
+    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[MV]](s64)
     ; X86-NEXT: RET 0, implicit [[COPY]](s64)
     %0:_(s64) = IMPLICIT_DEF
     %1:_(s64) = G_CTTZ_ZERO_UNDEF %0
     %2:_(s64) = COPY %1(s64)
     RET 0, implicit %2
 ...
 ---
 name:            test_cttz32

llvm/test/CodeGen/X86/GlobalISel/legalize-trailing-zeros.mir

 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 2
 # RUN: llc -mtriple=x86_64-linux-gnu -mattr=+bmi -run-pass=legalizer %s -o - | FileCheck %s --check-prefixes=CHECK,X64
 # RUN: llc -mtriple=i386-linux-gnu -mattr=+bmi -run-pass=legalizer -global-isel-abort=2 -pass-remarks-missed='gisel*'  %s 2>%t -o - | FileCheck %s --check-prefixes=CHECK,X86
-# RUN: FileCheck -check-prefix=ERR32  %s < %t
-
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %6:_(s64) = G_SELECT %10:_(s1), %13:_, %14:_ (in function: test_cttz35)
-# ERR32: remark: <unknown>:0:0: unable to legalize instruction: %1:_(s64) = G_SELECT %6:_(s1), %9:_, %10:_ (in function: test_cttz64)
 
 # test count leading zeros for s16, s32, and s64
 
 ---
 name:            test_cttz35
 alignment:       16
 legalized:       false
 regBankSelected: false
bb.1:
     ; X86-NEXT: [[OR:%[0-9]+]]:_(s64) = G_OR [[ANYEXT]], [[C]]
     ; X86-NEXT: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[OR]](s64)
     ; X86-NEXT: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
     ; X86-NEXT: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[UV]](s32), [[C1]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV1]](s32)
     ; X86-NEXT: [[C2:%[0-9]+]]:_(s64) = G_CONSTANT i64 32
     ; X86-NEXT: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[CTTZ_ZERO_UNDEF]], [[C2]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF1:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV]](s32)
-    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[ICMP]](s1), [[ADD]], [[CTTZ_ZERO_UNDEF1]]
-    ; X86-NEXT: [[TRUNC:%[0-9]+]]:_(s35) = G_TRUNC [[SELECT]](s64)
+    ; X86-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ADD]](s64)
+    ; X86-NEXT: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CTTZ_ZERO_UNDEF1]](s64)
+    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[UV2]], [[UV4]]
+    ; X86-NEXT: [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[ICMP]](s1)
+    ; X86-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ZEXT]](s8), [[UV3]], [[UV5]]
+    ; X86-NEXT: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[SELECT]](s32), [[SELECT1]](s32)
+    ; X86-NEXT: [[TRUNC:%[0-9]+]]:_(s35) = G_TRUNC [[MV]](s64)
     ; X86-NEXT: [[COPY:%[0-9]+]]:_(s35) = COPY [[TRUNC]](s35)
     ; X86-NEXT: RET 0, implicit [[COPY]](s35)
     %0:_(s35) = IMPLICIT_DEF
     %1:_(s35) = G_CTTZ %0
     %2:_(s35) = COPY %1(s35)
     RET 0, implicit %2
 ...
 ---
bb.1:
     ; X86: [[DEF:%[0-9]+]]:_(s64) = IMPLICIT_DEF
     ; X86-NEXT: [[UV:%[0-9]+]]:_(s32), [[UV1:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[DEF]](s64)
     ; X86-NEXT: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 0
     ; X86-NEXT: [[ICMP:%[0-9]+]]:_(s1) = G_ICMP intpred(eq), [[UV]](s32), [[C]]
     ; X86-NEXT: [[CTTZ:%[0-9]+]]:_(s64) = G_CTTZ [[UV1]](s32)
     ; X86-NEXT: [[C1:%[0-9]+]]:_(s64) = G_CONSTANT i64 32
     ; X86-NEXT: [[ADD:%[0-9]+]]:_(s64) = G_ADD [[CTTZ]], [[C1]]
     ; X86-NEXT: [[CTTZ_ZERO_UNDEF:%[0-9]+]]:_(s64) = G_CTTZ_ZERO_UNDEF [[UV]](s32)
-    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT [[ICMP]](s1), [[ADD]], [[CTTZ_ZERO_UNDEF]]
-    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[SELECT]](s64)
+    ; X86-NEXT: [[UV2:%[0-9]+]]:_(s32), [[UV3:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[ADD]](s64)
+    ; X86-NEXT: [[UV4:%[0-9]+]]:_(s32), [[UV5:%[0-9]+]]:_(s32) = G_UNMERGE_VALUES [[CTTZ_ZERO_UNDEF]](s64)
+    ; X86-NEXT: [[SELECT:%[0-9]+]]:_(s32) = G_SELECT [[ICMP]](s1), [[UV2]], [[UV4]]
+    ; X86-NEXT: [[ZEXT:%[0-9]+]]:_(s8) = G_ZEXT [[ICMP]](s1)
+    ; X86-NEXT: [[SELECT1:%[0-9]+]]:_(s32) = G_SELECT [[ZEXT]](s8), [[UV3]], [[UV5]]
+    ; X86-NEXT: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES [[SELECT]](s32), [[SELECT1]](s32)
+    ; X86-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY [[MV]](s64)
     ; X86-NEXT: RET 0, implicit [[COPY]](s64)
     %0:_(s64) = IMPLICIT_DEF
     %1:_(s64) = G_CTTZ %0
     %2:_(s64) = COPY %1(s64)
     RET 0, implicit %2
 ...
 ---
 name:            test_cttz32