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Change encoding of instruction operands in bitcode binaries to be relative

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to the instruction position.  The old encoding would give an absolute
ID which counts up within a function, and only resets at the next function.

I.e., Instead of having:

... = icmp eq i32 n-1, n-2
br i1 ..., label %bb1, label %bb2

it will now be roughly:

... = icmp eq i32 1, 2
br i1 1, label %bb1, label %bb2

This makes it so that ids remain relatively small and can be encoded
in fewer bits.

With this encoding, forward reference operands will be given
negative-valued IDs.  Use signed VBRs for the most common case
of forward references, which is phi instructions.

To retain backward compatibility we bump the bitcode version
from 0 to 1 to distinguish between the different encodings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165739 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jan Wen Voung
2012-10-11 20:20:40 +00:00
parent 81eb88f7d2
commit d9a3bad448
5 changed files with 236 additions and 91 deletions
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49
test/Bitcode/function-encoding-rel-operands.ll Normal file
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; Basic sanity test to check that instruction operands are encoded with
; relative IDs.
; RUN: llvm-as < %s | llvm-bcanalyzer -dump | FileCheck %s
; CHECK: FUNCTION_BLOCK
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_RET {{.*}}op0=1
define i32 @test_int_binops(i32 %a) nounwind {
entry:
%0 = add i32 %a, %a
%1 = sub i32 %0, %0
%2 = mul i32 %1, %1
ret i32 %2
}
; CHECK: FUNCTION_BLOCK
; CHECK: INST_CAST {{.*}}op0=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_BINOP {{.*}}op0=1 op1=1
; CHECK: INST_RET {{.*}}op0=1
define double @test_float_binops(i32 %a) nounwind {
%1 = sitofp i32 %a to double
%2 = fadd double %1, %1
%3 = fsub double %2, %2
%4 = fmul double %3, %3
%5 = fdiv double %4, %4
ret double %5
}
; CHECK: FUNCTION_BLOCK
; skip checking operands of INST_INBOUNDS_GEP since that depends on ordering
; between literals and the formal parameters.
; CHECK: INST_INBOUNDS_GEP {{.*}}
; CHECK: INST_LOAD {{.*}}op0=1 {{.*}}
; CHECK: INST_CMP2 op0=1 {{.*}}
; CHECK: INST_RET {{.*}}op0=1
define i1 @test_load(i32 %a, {i32, i32}* %ptr) nounwind {
entry:
%0 = getelementptr inbounds {i32, i32}* %ptr, i32 %a, i32 0
%1 = load i32* %0
%2 = icmp eq i32 %1, %a
ret i1 %2
}