| Message ID | CACUk7=X912WSUxH8UMrzT7syTVCLbXqhScQLAdifDBpgAnj7QA@mail.gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index d1d0c22..bfdac51 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -17654,8 +17654,8 @@ arm_print_operand (FILE *stream, rtx x, int code) /* Only certain alignment specifiers are supported by the hardware. */ if (memsize == 16 && (align % 32) == 0) align_bits = 256; - else if ((memsize == 8 || memsize == 16) && (align % 16) == 0) - align_bits = 128; + else if ((memsize == 16) && (align % 16) == 0) + align_bits = 128; else if ((align % 8) == 0) align_bits = 64; else
Hi, This fixes a latent issue in arm_print_operand where we would have generated a 128 bit alignment hint for any neon instruction that used the %A notation for printing memory addresses. Given that you can never have the load of a 64 bit quantity with an 128 bit alignment (indeed the list of instructions that I could think of that we might generate for this purpose is as below.) vld1.8 d0, [r0] vld1.16 d0, [r0] vld1.32 d0, [r0] vld1.64 d0, [r0] vld2.32 {d0[0], d1[0]}, [r0] vld4.16 {d0[0], d1[0], d2[0], D3[0]}, [r0] This is not an issue today for the following reasons : From the list above: 1. The first 4 instructions will not come out of the compiler today (we put out vldr's or vldmia) instructions for auto-vectorized code. Indeed I found this only when I replaced the vldmia's and the vldr's with vld1's. 2. The last 2 instructions only come out of intrinsics. The first 4 will also get generated with the intrinsics but ..... we get away with this because of the type punning in arm_neon.h Even in the event we use this in that form, I doubt if we'll ever change that situation. I was able to trigger this when I tried to get the backend to generate vld1.64 instructions for appropriate vector modes instead of vldmia / vstmia in little endian configurations. (That will follow once testing completes) Ok ? cheers Ramana 2011-12-08 Ramana Radhakrishnan <ramana.radhakrishnan@linaro.org> * config/arm/arm.c (arm_print_operand): Only allow hints of 128 bits for 16 byte loads.