Ping~ Original posted here:
https://gcc.gnu.org/ml/gcc-patches/2014-06/msg01492.html Thanks, Yufeng On 06/18/14 17:35, Yufeng Zhang wrote:
This time with patch... Apologize. Yufeng On 06/18/14 17:31, Yufeng Zhang wrote:Hi, This patch improves the code-gen of -marm in the case of two-dimensional array access. Given the following code: typedef struct { int x,y,a,b; } X; int f7a(X p[][4], int x, int y) { return p[x][y].a; } The code-gen on -O2 -marm -mcpu=cortex-a15 is currently mov r2, r2, asl #4 add r1, r2, r1, asl #6 add r0, r0, r1 ldr r0, [r0, #8] bx lr With the patch, we'll get: add r1, r0, r1, lsl #6 add r2, r1, r2, lsl #4 ldr r0, [r2, #8] bx lr The -mthumb code-gen had been OK. The patch has passed the bootstrapping on cortex-a15 and the arm-none-eabi regtest, with no code-gen difference in spec2k (unfortunately). OK for the trunk? Thanks, Yufeng gcc/ * config/arm/arm.c (arm_reassoc_shifts_in_address): New declaration and new function. (arm_legitimize_address): Call the new functions. (thumb_legitimize_address): Prefix the declaration with static. gcc/testsuite/ * gcc.target/arm/shifted-add-1.c: New test. * gcc.target/arm/shifted-add-2.c: Ditto.
