X86: when SSE1 isn't available, f32 arguments are incorrectly passes as f64 #1861
Comments
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It is passing a 64-bit value for the 32-bit float, obviously wrong. It does not do this without -mcpu=i486. |
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Very interesting. Investigating. |
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Okay, the problem here is simple enough. f32 is not a legal datatype when you don't have SSE, so the call This obviously loses important information for the call, but it seems like we need to extend the ISD::CALL |
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Perhaps change such parameters to bitcast to i32. That's sort of what's going on in a calling convention |
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Yep, that sounds like a good plan Dale. Can you please do this? It'll be in the ISD::CALL handling code of -Chris |
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That'll teach me to comment. |
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:) It's a good chance to get exposure to the legalizer :) |
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Yeah, I know. Forgot a smiley I guess. |
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The fix above was removed in favor of: |
refs llvm#1861 test仕様書に基づいたテストの変更 See merge request a64fx-swpl/llvm-project!94
Extended Description
llvm-gcc is miscompiling the following c code:
#define _ISOC9X_SOURCE 1
#include <math.h>
int main( void ) { return (lrintf(3.999f) > 0)?0:1; }
laurov@laurov-laptop:/tmp$ gcc test.c -o test -lm
laurov@laurov-laptop:/tmp$ ./test
laurov@laurov-laptop:/tmp$ echo $?
0
laurov@laurov-laptop:/tmp$ llvm-gcc test.c -o test -lm
laurov@laurov-laptop:/tmp$ ./test
laurov@laurov-laptop:/tmp$ echo $?
1
To reproduce this bug with llc must be used "llc -disable-fp-elim -fast -mcpu=i486".
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