Test Failure: Transforms/InstCombine/ffs-i16.ll

Test source: git

Log:

Source: <stdin>
-- 1. ModuleToFunctionPassAdaptor
-- 1. PassManager<Function> : Skipping NOP
-- 2. InstCombinePass

----------------------------------------
define void @fold_ffs(i16 %x) {
%0:
  %n0 = ffs i16 0
  call void @sink(i16 %n0)
  %n1 = ffs i16 1
  call void @sink(i16 %n1)
  %nx = ffs i16 %x
  call void @sink(i16 %nx)
  ret void
}
Transformation seems to be correct! (syntactically equal)

-- 3. InstCombinePass

----------------------------------------
define void @fold_ffs(i16 %x) {
%0:
  %n0 = ffs i16 0
  call void @sink(i16 %n0)
  %n1 = ffs i16 1
  call void @sink(i16 %n1)
  %nx = ffs i16 %x
  call void @sink(i16 %nx)
  ret void
}
=>
define void @fold_ffs(i16 %x) {
%0:
  call void @sink(i16 0)
  call void @sink(i16 1)
  %cttz = cttz i16 %x, 1
  %range_l#0%cttz = icmp sge i16 %cttz, 0
  %range_h#0%cttz = icmp slt i16 %cttz, 17
  %range#0%cttz = and i1 %range_l#0%cttz, %range_h#0%cttz
  assume_non_poison i1 %range#0%cttz
  %1 = add nsw nuw i16 %cttz, 1
  %.not = icmp eq i16 %x, 0
  %2 = select i1 %.not, i16 0, i16 %1
  call void @sink(i16 %2)
  ret void
}
Transformation doesn't verify! (unsound)
ERROR: Source is more defined than target

Example:
i16 %x = undef

Source:
i16 %n0 = #x0000 (0)
Function @sink returned
i16 %n1 = #x0001 (1)
Function @sink returned
i16 %nx = #x0000 (0)	[based on undef value]
Function @sink returned

SOURCE MEMORY STATE
===================
NON-LOCAL BLOCKS:
Block 0 >	size: 0	align: 1	alloc type: 0
Block 1 >	size: 0	align: 1	alloc type: 0

Target:
Function @sink returned
Function @sink returned
i16 %cttz = #x0000 (0)
i1 %range_l#0%cttz = #x1 (1)
i1 %range_h#0%cttz = #x1 (1)
i1 %range#0%cttz = #x1 (1)
i16 %1 = poison
i1 %.not = #x0 (0)
i16 %2 = poison
Function @sink triggered UB


Pass: InstCombinePass
Command line: '/home/nlopes/llvm/build/bin/opt' '-load=/home/nlopes/alive2/build/tv/tv.so' '-load-pass-plugin=/home/nlopes/alive2/build/tv/tv.so' '-tv-exit-on-error' '-mtriple=avr-linux' '-passes=instcombine' '-S' '-tv-smt-to=20000' '-tv-report-dir=/home/nlopes/alive2/build/logs' '-tv-smt-stats'


------------------- SMT STATS -------------------
Num queries: 4
Num invalid: 0
Num skips:   0
Num trivial: 9 (69.2%)
Num timeout: 0 (0.0%)
Num errors:  0 (0.0%)
Num SAT:     4 (100.0%)
Num UNSAT:   0 (0.0%)
Alive2: Transform doesn't verify; aborting!

stderr:

+ : 'RUN: at line 6'
+ /home/nlopes/alive2/build/opt-alive.sh -mtriple=avr-linux -passes=instcombine -S
+ /bitbucket/nlopes/llvm/build/bin/FileCheck /bitbucket/nlopes/llvm/llvm/test/Transforms/InstCombine/ffs-i16.ll

FileCheck error: '<stdin>' is empty.
FileCheck command line:  /bitbucket/nlopes/llvm/build/bin/FileCheck /bitbucket/nlopes/llvm/llvm/test/Transforms/InstCombine/ffs-i16.ll

NOTE: This test would pass if undef didn't exist!

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