llvm-mirror/2008-05-31-BoolOverflow.ll at 53ce5fa5ceacb3dbccc74ee1d12b2c2c68d25664 - llvm-mirror - Git.je (Gitea)

RPCS3/llvm-mirror

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Chris Lattner 43a47ddd89 Fix the CBE's handling of instructions whose result is an i1. Previously,

we did not truncate the value down to i1 with (x&1).  This caused a problem
when the computation of x was nontrivial, for example, "add i1 1, 1" would 
return 2 instead of 0.

This makes the testcase compile into:

...
  llvm_cbe_t = (((llvm_cbe_r == 0u) + (llvm_cbe_r == 0u))&1);
  llvm_cbe_u = (((unsigned int )(bool )llvm_cbe_t));
...

instead of:

...
  llvm_cbe_t = ((llvm_cbe_r == 0u) + (llvm_cbe_r == 0u));
  llvm_cbe_u = (((unsigned int )(bool )llvm_cbe_t));
...

This fixes a miscompilation of mediabench/adpcm/rawdaudio/rawdaudio and
403.gcc with the CBE, regressions from LLVM 2.2. Tanya, please pull 
this into the release branch.

llvm-svn: 51813

2008-05-31 09:23:55 +00:00

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 ; RUN: llvm-as < %s | llc -march=c | grep {llvm_cbe_t.*&1}
 define i32 @test(i32 %r) {
   %s = icmp eq i32 %r, 0
   %t = add i1 %s, %s
   %u = zext i1 %t to i32
   br i1 %t, label %A, label %B
 A:
   ret i32 %u
 B:
   %v = select i1 %t, i32 %r, i32 %u
   ret i32 %v
 }